diff --git a/.github/decodekey.sh b/.github/decodekey.sh
new file mode 100755
index 000000000..ac7c2c58f
--- /dev/null
+++ b/.github/decodekey.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+
+# echo $PGP_SECRET | base64 --decode | gpg --import --batch --yes --pinentry-mode loopback --passphrase $PGP_PASSPHRASE
+echo $PGP_SECRET | base64 --decode | gpg --batch --import
diff --git a/.github/workflows/release.txt b/.github/workflows/release.txt
new file mode 100644
index 000000000..30bad8521
--- /dev/null
+++ b/.github/workflows/release.txt
@@ -0,0 +1,32 @@
+name: Release
+on:
+  push:
+    tags: ["*"]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      # define Java options for both official sbt and sbt-extras
+      JAVA_OPTS: -Xms2048M -Xmx2048M -Xss6M -XX:ReservedCodeCacheSize=256M -Dfile.encoding=UTF-8
+      JVM_OPTS:  -Xms2048M -Xmx2048M -Xss6M -XX:ReservedCodeCacheSize=256M -Dfile.encoding=UTF-8
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Setup JDK
+      uses: actions/setup-java@v3
+      with:
+        distribution: "temurin"
+        java-version: 8
+        cache: sbt
+    - name: Release
+      env:
+        SONATYPE_PASSWORD: ${{ secrets.SONATYPE_PASSWORD }}
+        SONATYPE_USERNAME: ${{ secrets.SONATYPE_USERNAME }}
+        PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}
+        PGP_SECRET: ${{ secrets.PGP_SECRET }}
+        CI_CLEAN: clean
+        CI_RELEASE: publishSigned
+        CI_SONATYPE_RELEASE: version
+      run: |
+        sbt ci-release
diff --git a/README.markdown b/README.markdown
new file mode 100644
index 000000000..7fefdbc00
--- /dev/null
+++ b/README.markdown
@@ -0,0 +1,199 @@
+sbt-projectmatrix
+=================
+
+cross building using subprojects.
+
+This is an experimental plugin that implements better cross building.
+
+setup
+-----
+
+**Requirements**: Requires sbt 1.2.0 or above.
+
+In `project/plugins.sbt`:
+
+```scala
+addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % "0.10.0")
+
+// add also the following for Scala.js support
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.10.1")
+```
+
+usage
+-----
+
+### building against multiple Scala versions
+
+After adding sbt-projectmatrix to your build, here's how you can set up a matrix with two Scala versions.
+
+```scala
+ThisBuild / organization := "com.example"
+ThisBuild / scalaVersion := "2.13.3"
+ThisBuild / version      := "0.1.0-SNAPSHOT"
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    name := "core"
+  )
+  .jvmPlatform(scalaVersions = Seq("2.13.3", "2.12.12"))
+```
+
+This will create subprojects `core` and `core2_12`.
+Unlike `++` style stateful cross building, these will build in parallel.
+
+### two matrices
+
+It gets more interesting if you have more than one matrix.
+
+```scala
+ThisBuild / organization := "com.example"
+ThisBuild / scalaVersion := "2.13.3"
+ThisBuild / version      := "0.1.0-SNAPSHOT"
+
+// uncomment if you want root
+// lazy val root = (project in file("."))
+//   .aggregate(core.projectRefs ++ app.projectRefs: _*)
+//   .settings(
+//   )
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    name := "core"
+  )
+  .jvmPlatform(scalaVersions = Seq("2.13.3", "2.12.12"))
+
+lazy val app = (projectMatrix in file("app"))
+  .dependsOn(core)
+  .settings(
+    name := "app"
+  )
+  .jvmPlatform(scalaVersions = Seq("2.13.3"))
+```
+
+This is an example where `core` builds against Scala 2.12 and 2.13, but app only builds for one of them.
+
+### Scala.js support
+
+[Scala.js](http://scala-js.org/) support was added in sbt-projectmatrix 0.2.0.
+To use this, you need to setup sbt-scalajs as well:
+
+```scala
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    name := "core"
+  )
+  .jsPlatform(scalaVersions = Seq("2.12.12", "2.11.12"))
+```
+
+This will create subprojects `coreJS2_11` and `coreJS2_12`.
+
+### Scala Native support
+
+[Scala Native](http://scala-native.org) support will be added in upcoming release.
+To use this, you need to setup sbt-scala-native` as well:
+
+```scala
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    name := "core"
+  )
+  .nativePlatform(scalaVersions = Seq("2.11.12"))
+```
+
+This will create subproject `coreNative2_11`.
+
+### parallel cross-library building
+
+The rows can also be used for parallel cross-library building.
+For example, if you want to build against Config 1.2 and Config 1.3, you can do something like this:
+
+In `project/ConfigAxis.scala`:
+
+```scala
+import sbt._
+
+case class ConfigAxis(idSuffix: String, directorySuffix: String) extends VirtualAxis.WeakAxis {
+}
+```
+
+In `build.sbt`:
+
+```scala
+ThisBuild / organization := "com.example"
+ThisBuild / version := "0.1.0-SNAPSHOT"
+
+lazy val config12 = ConfigAxis("Config1_2", "config1.2")
+lazy val config13 = ConfigAxis("Config1_3", "config1.3")
+
+lazy val scala212 = "2.12.10"
+lazy val scala211 = "2.11.12"
+
+lazy val app = (projectMatrix in file("app"))
+  .settings(
+    name := "app"
+  )
+  .customRow(
+    scalaVersions = Seq(scala212, scala211),
+    axisValues = Seq(config12, VirtualAxis.jvm),
+    _.settings(
+      moduleName := name.value + "_config1.2",
+      libraryDependencies += "com.typesafe" % "config" % "1.2.1"
+    )
+  )
+  .customRow(
+    scalaVersions = Seq(scala212, scala211),
+    axisValues = Seq(config13, VirtualAxis.jvm),
+    _.settings(
+      moduleName := name.value + "_config1.3",
+      libraryDependencies += "com.typesafe" % "config" % "1.3.3"
+    )
+  )
+```
+
+This will create `appConfig1_22_11`, `appConfig1_22_12`, and `appConfig1_32_12` respectively producing `app_config1.3_2.12`, `app_config1.2_2.11`, and `app_config1.2_2.12` artifacts.
+
+### referencing the generated subprojects
+
+You might want to reference to one of the projects within `build.sbt`.
+
+```scala
+lazy val core12 = core.jvm("2.12.8")
+
+lazy val appConfig12_212 = app.finder(config13, VirtualAxis.jvm)("2.12.8")
+```
+
+In the above `core12` returns `Project` type.
+
+### accessing axes from subprojects
+
+Each generated subproject can access the values for all the axes using `virtualAxes` key:
+
+```scala
+lazy val platformTest = settingKey[String]("")
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    name := "core"
+  )
+  .jsPlatform(scalaVersions = Seq("2.12.12", "2.11.12"))
+  .jvmPlatform(scalaVersion = Seq("2.12.12", "2.13.3"))
+  .settings(
+    platformTest := {
+      if(virtualAxes.value.contains(VirtualAxis.jvm))
+        "JVM project"
+      else
+        "JS project"
+    }
+  )
+```
+
+credits
+-------
+
+- The idea of representing cross build using subproject was pionieered by Tobias Schlatter's work on Scala.js plugin, which was later expanded to [ sbt-crossproject](https://github.com/portable-scala/sbt-crossproject). However, this only addresses the platform (JVM, JS, Native) cross building.
+- [sbt-cross](https://github.com/lucidsoftware/sbt-cross) written by Paul Draper in 2015 implements cross building across Scala versions.
+
+license
+-------
+
+MIT License
diff --git a/src/main/scala/sbt/VirtualAxis.scala b/src/main/scala/sbt/VirtualAxis.scala
new file mode 100644
index 000000000..e601a14d2
--- /dev/null
+++ b/src/main/scala/sbt/VirtualAxis.scala
@@ -0,0 +1,118 @@
+package sbt
+
+import sbt.librarymanagement.CrossVersion.{ binaryScalaVersion, partialVersion }
+
+/** Virtual Axis represents a parameter to a project matrix row. */
+sealed abstract class VirtualAxis {
+  def directorySuffix: String
+
+  def idSuffix: String
+
+  /* The order to sort the suffixes if there were multiple axes. */
+  def suffixOrder: Int = 50
+}
+
+object VirtualAxis {
+  /**
+   * WeakAxis allows a row to depend on another row with Zero value.
+   * For example, Scala version can be Zero for Java project, and it's ok.
+   */
+  abstract class WeakAxis extends VirtualAxis
+
+  /** StrongAxis requires a row to depend on another row with the same selected value. */
+  abstract class StrongAxis extends VirtualAxis
+
+
+  def isMatch(lhs: Seq[VirtualAxis], rhs: Seq[VirtualAxis]): Boolean =
+    lhs.forall(isStronglyCompatible(_, rhs)) && rhs.forall(isStronglyCompatible(_, lhs))
+
+  private[sbt] def isStronglyCompatible(v: VirtualAxis, stack: Seq[VirtualAxis]): Boolean =
+    v match {
+      case v: WeakAxis =>
+        val clazz = v.getClass
+        stack.contains(v) || !stack.exists(_.getClass == clazz)
+      case v: StrongAxis =>
+        stack.contains(v)
+    }
+
+  def isSecondaryMatch(lhs: Seq[VirtualAxis], rhs: Seq[VirtualAxis]): Boolean =
+    lhs.forall(isSecondaryCompatible(_, rhs)) && rhs.forall(isSecondaryCompatible(_, lhs))
+
+  def isSecondaryCompatible(v: VirtualAxis, stack: Seq[VirtualAxis]): Boolean =
+    v match {
+      case v: ScalaVersionAxis =>
+        val thatSVOpt = (stack collect {
+          case x: ScalaVersionAxis => x
+        }).headOption
+        thatSVOpt match {
+          case Some(ScalaVersionAxis(sv, _)) =>
+            (v.scalaVersion == sv) ||
+            isScala2Scala3Sandwich(partialVersion(v.scalaVersion), partialVersion(sv))
+          case _ => true
+        }
+      case _ =>
+        isStronglyCompatible(v, stack)
+    }
+
+  private[sbt] def isScala2Scala3Sandwich(sbv1: Option[(Long, Long)], sbv2: Option[(Long, Long)]): Boolean = {
+    def str(x: Option[(Long, Long)]): String =
+      x match {
+        case Some((a, b)) => s"$a.$b"
+        case _            => "0.0"
+      }
+    isScala2Scala3Sandwich(str(sbv1), str(sbv2))
+  }
+
+  private[sbt] def isScala2Scala3Sandwich(sbv1: String, sbv2: String): Boolean = {
+    def compare(a: String, b: String): Boolean =
+      a == "2.13" && (b.startsWith("0.") || b.startsWith("3."))
+    compare(sbv1, sbv2) || compare(sbv2, sbv1)
+  }
+
+  // This admits partial Scala version
+  private[sbt] def isPartialVersionEquals(ax1: VirtualAxis, ax2: VirtualAxis): Boolean = {
+    (ax1, ax2) match {
+      case (ax1: ScalaVersionAxis, ax2: ScalaVersionAxis) =>
+        (ax1 == ax2) || (ax1.value == ax2.value)
+      case _ => ax1 == ax2
+    }
+  }
+
+  case class ScalaVersionAxis(scalaVersion: String, value: String) extends WeakAxis {
+    override def idSuffix: String = directorySuffix.replaceAll("""\W+""", "_")
+    override val suffixOrder: Int = 100
+    override def directorySuffix: String = value
+
+    // use only the scalaVersion field for equality
+    override def equals(obj: Any): Boolean = {
+      if (obj.isInstanceOf[AnyRef] && (this eq obj.asInstanceOf[AnyRef])) true
+      else if (!obj.isInstanceOf[ScalaVersionAxis]) false
+      else {
+        val o = obj.asInstanceOf[ScalaVersionAxis]
+        this.scalaVersion == o.scalaVersion
+      }
+    }
+    override def hashCode: Int = {
+      37 * (17 + "sbt.ScalaVersionAxis".hashCode()) + scalaVersion.hashCode()
+    }
+  }
+
+  case class PlatformAxis(value: String, idSuffix: String, directorySuffix: String) extends StrongAxis {
+    override val suffixOrder: Int = 80
+  }
+
+  def scalaPartialVersion(scalaVersion: String): ScalaVersionAxis =
+    partialVersion(scalaVersion) match {
+      case Some((m, n)) => scalaVersionAxis(scalaVersion, s"$m.$n")
+      case _            => scalaVersionAxis(scalaVersion, scalaVersion)
+    }
+  def scalaABIVersion(scalaVersion: String): ScalaVersionAxis =
+    scalaVersionAxis(scalaVersion, binaryScalaVersion(scalaVersion))
+
+  def scalaVersionAxis(scalaVersion: String, value: String) =
+    ScalaVersionAxis(scalaVersion, value)
+
+  val jvm: PlatformAxis = PlatformAxis("jvm", "JVM", "jvm")
+  val js: PlatformAxis = PlatformAxis("js", "JS", "js")
+  val native: PlatformAxis = PlatformAxis("native", "Native", "native")
+}
diff --git a/src/main/scala/sbt/internal/ProjectMatrix.scala b/src/main/scala/sbt/internal/ProjectMatrix.scala
new file mode 100644
index 000000000..1e426bfdd
--- /dev/null
+++ b/src/main/scala/sbt/internal/ProjectMatrix.scala
@@ -0,0 +1,633 @@
+package sbt
+package internal
+
+import java.util.Locale
+import scala.collection.immutable.ListMap
+import scala.collection.mutable
+import Keys._
+import scala.util.Try
+import sbt.internal.inc.ReflectUtilities
+
+import sbtprojectmatrix.ProjectMatrixKeys
+
+/**
+ * A project matrix is an implementation of a composite project
+ * that represents cross building across some axis (such as platform)
+ * and Scala version.
+ *
+ *  {{{
+ *  lazy val core = (projectMatrix in file("core"))
+ *    .settings(
+ *      name := "core"
+ *    )
+ *    .jvmPlatform(Seq("2.12.6", "2.11.12"))
+ *  }}}
+ */
+sealed trait ProjectMatrix extends CompositeProject {
+  def id: String
+
+  /** The base directory for the project matrix.*/
+  def base: sbt.File
+
+  def withId(id: String): ProjectMatrix
+
+  /** Sets the base directory for this project matrix.*/
+  def in(dir: sbt.File): ProjectMatrix
+
+  /** Adds new configurations directly to this project.  To override an existing configuration, use `overrideConfigs`. */
+  def configs(cs: Configuration*): ProjectMatrix
+
+  /** Adds classpath dependencies on internal or external projects. */
+  def dependsOn(deps: MatrixClasspathDep[ProjectMatrixReference]*): ProjectMatrix
+
+  /** Adds classpath dependencies on internal or external non-matrix projects. */
+  def dependsOn(deps: ClasspathDep[ProjectReference]*)(implicit dummyImplicit: DummyImplicit): ProjectMatrix
+
+  /**
+   * Adds projects to be aggregated.  When a user requests a task to run on this project from the command line,
+   * the task will also be run in aggregated projects.
+   */
+  def aggregate(refs: ProjectMatrixReference*): ProjectMatrix
+
+  /**
+   * Allows non-matrix projects to be aggregated in a matrix project.
+   */
+  def aggregate(refs: ProjectReference*)(implicit dummyImplicit: DummyImplicit): ProjectMatrix
+
+  /** Appends settings to the current settings sequence for this project. */
+  def settings(ss: Def.SettingsDefinition*): ProjectMatrix
+
+  /**
+   * Sets the [[sbt.AutoPlugin]]s of this project.
+   * An [[sbt.AutoPlugin]] is a common label that is used by plugins to determine what settings, if any, to enable on a project.
+   */
+  def enablePlugins(ns: Plugins*): ProjectMatrix
+
+  /** Disable the given plugins on this project. */
+  def disablePlugins(ps: AutoPlugin*): ProjectMatrix
+
+  /**
+   * Applies the given functions to this Project.
+   * The second function is applied to the result of applying the first to this Project and so on.
+   * The intended use is a convenience for applying default configuration provided by a plugin.
+   */
+  def configure(transforms: (Project => Project)*): ProjectMatrix
+
+  /**
+   * If autoScalaLibrary is false, add non-Scala row.
+   * Otherwise, add custom rows for each scalaVersions.
+   */
+  def customRow(
+    autoScalaLibrary: Boolean,
+    scalaVersions: Seq[String],
+    axisValues: Seq[VirtualAxis],
+    process: Project => Project
+  ): ProjectMatrix
+
+  def customRow(
+    scalaVersions: Seq[String],
+    axisValues: Seq[VirtualAxis],
+    process: Project => Project
+  ): ProjectMatrix
+
+  def customRow(
+    autoScalaLibrary: Boolean,
+    axisValues: Seq[VirtualAxis],
+    process: Project => Project
+  ): ProjectMatrix
+
+  def customRow(
+    scalaVersions: Seq[String],
+    axisValues: Seq[VirtualAxis],
+    settings: Seq[Setting[_]]
+  ): ProjectMatrix
+
+  def customRow(
+    autoScalaLibrary: Boolean,
+    axisValues: Seq[VirtualAxis],
+    settings: Seq[Setting[_]]
+  ): ProjectMatrix
+
+  def jvmPlatform(scalaVersions: Seq[String]): ProjectMatrix
+  def jvmPlatform(autoScalaLibrary: Boolean): ProjectMatrix
+  def jvmPlatform(scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix
+  def jvmPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], settings: Seq[Setting[_]]): ProjectMatrix
+  def jvmPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], configure: Project => Project): ProjectMatrix
+  def jvmPlatform(autoScalaLibrary: Boolean, scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix
+  def jvm: ProjectFinder
+
+  def jsPlatform(scalaVersions: Seq[String]): ProjectMatrix
+  def jsPlatform(scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix
+  def jsPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], settings: Seq[Setting[_]]): ProjectMatrix
+  def jsPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], configure: Project => Project): ProjectMatrix
+  def js: ProjectFinder
+
+  def nativePlatform(scalaVersions: Seq[String]): ProjectMatrix
+  def nativePlatform(scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix
+  def nativePlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], settings: Seq[Setting[_]]): ProjectMatrix
+  def nativePlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], configure: Project => Project): ProjectMatrix
+  def native: ProjectFinder
+
+  def defaultAxes(axes: VirtualAxis*): ProjectMatrix
+
+  def projectRefs: Seq[ProjectReference]
+
+  def filterProjects(axisValues: Seq[VirtualAxis]): Seq[Project]
+  def filterProjects(autoScalaLibrary: Boolean, axisValues: Seq[VirtualAxis]): Seq[Project]
+  def finder(axisValues: VirtualAxis*): ProjectFinder
+  def allProjects(): Seq[(Project, Seq[VirtualAxis])]
+
+  // resolve to the closest match for the given row
+  private[sbt] def resolveMatch(thatRow: ProjectMatrix.ProjectRow): ProjectReference
+}
+
+/** Represents a reference to a project matrix with an optional configuration string.
+ */
+sealed trait MatrixClasspathDep[MR <: ProjectMatrixReference] {
+  def matrix: MR; def configuration: Option[String]
+}
+
+trait ProjectFinder {
+  def apply(scalaVersion: String): Project
+  def apply(autoScalaLibrary: Boolean): Project
+  def get: Seq[Project]
+}
+
+object ProjectMatrix {
+  import sbt.io.syntax._
+
+  val jvmIdSuffix: String = "JVM"
+  val jvmDirectorySuffix: String = "-jvm"
+  val jsIdSuffix: String = "JS"
+  val jsDirectorySuffix: String = "-js"
+  val nativeIdSuffix: String = "Native"
+  val nativeDirectorySuffix: String = "-native"
+
+  private[sbt] val allMatrices: mutable.Map[String, ProjectMatrix] = mutable.Map.empty
+
+  /** A row in the project matrix, typically representing a platform + Scala version.
+   */
+  final class ProjectRow(
+      val autoScalaLibrary: Boolean,
+      val axisValues: Seq[VirtualAxis],
+      val process: Project => Project
+  ) {
+    def scalaVersionOpt: Option[String] =
+      if (autoScalaLibrary)
+        (axisValues collect {
+          case sv: VirtualAxis.ScalaVersionAxis => sv.scalaVersion
+        }).headOption
+      else None
+
+    def isMatch(that: ProjectRow): Boolean =
+      VirtualAxis.isMatch(this.axisValues, that.axisValues)
+
+    def isSecondaryMatch(that: ProjectRow): Boolean =
+      VirtualAxis.isSecondaryMatch(this.axisValues, that.axisValues)
+
+    override def toString: String = s"ProjectRow($autoScalaLibrary, $axisValues)"
+  }
+
+  final class ProjectMatrixReferenceSyntax(m: ProjectMatrixReference) {
+    def %(conf: String): ProjectMatrix.MatrixClasspathDependency =
+      ProjectMatrix.MatrixClasspathDependency(m, Some(conf))
+
+    def %(conf: Configuration): ProjectMatrix.MatrixClasspathDependency =
+      ProjectMatrix.MatrixClasspathDependency(m, Some(conf.name))
+  }
+
+  final case class MatrixClasspathDependency(
+      matrix: ProjectMatrixReference,
+      configuration: Option[String]
+  ) extends MatrixClasspathDep[ProjectMatrixReference]
+
+  private final class ProjectMatrixDef(
+      val id: String,
+      val base: sbt.File,
+      val scalaVersions: Seq[String],
+      val rows: Seq[ProjectRow],
+      val aggregate: Seq[ProjectMatrixReference],
+      val nonMatrixAggregate: Seq[ProjectReference],
+      val dependencies: Seq[MatrixClasspathDep[ProjectMatrixReference]],
+      val nonMatrixDependencies: Seq[ClasspathDep[ProjectReference]],
+      val settings: Seq[Def.Setting[_]],
+      val configurations: Seq[Configuration],
+      val plugins: Plugins,
+      val transforms: Seq[Project => Project],
+      val defAxes: Seq[VirtualAxis],
+  ) extends ProjectMatrix { self =>
+    lazy val resolvedMappings: ListMap[ProjectRow, Project] = resolveMappings
+    private def resolveProjectIds: Map[ProjectRow, String] = {
+      Map((for {
+        r <- rows
+      } yield {
+        val axes = r.axisValues.sortBy(_.suffixOrder)
+          .filterNot(isSortOfDefaultAxis)
+        val idSuffix = axes.map(_.idSuffix).mkString("")
+        val childId = self.id + idSuffix
+        r -> childId
+      }): _*)
+    }
+
+    private def isSortOfDefaultAxis(a: VirtualAxis): Boolean =
+      defAxes exists { da => VirtualAxis.isPartialVersionEquals(da, a) }
+
+    private def resolveMappings: ListMap[ProjectRow, Project] = {
+      val projectIds = resolveProjectIds
+
+      ListMap((for {
+        r <- rows
+      } yield {
+        val axes = r.axisValues.sortBy(_.suffixOrder)
+        val svDirSuffix = axes.map(_.directorySuffix).mkString("-")
+        val nonScalaDirSuffix = (axes filter {
+          case _: VirtualAxis.ScalaVersionAxis => false
+          case _                               => true
+        }).map(_.directorySuffix).mkString("-")
+
+        val platform = (axes collect {
+          case pa: VirtualAxis.PlatformAxis => pa
+        }).headOption.getOrElse(sys.error(s"platform axis is missing in $axes"))
+        val childId = projectIds(r)
+        val deps = dependencies.map { resolveMatrixDependency(_, r) } ++ nonMatrixDependencies
+        val aggs = aggregate.map {
+          case ref: LocalProjectMatrix =>
+            val other = lookupMatrix(ref)
+            resolveMatrixAggregate(other, r)
+        } ++ nonMatrixAggregate
+        val dotSbtMatrix = new java.io.File(".sbt") / "matrix"
+        IO.createDirectory(dotSbtMatrix)
+        val p = Project(childId, dotSbtMatrix / childId)
+          .dependsOn(deps: _*)
+          .aggregate(aggs: _*)
+          .setPlugins(plugins)
+          .configs(configurations: _*)
+          .settings(
+            name := self.id
+          )
+          .settings(
+            r.scalaVersionOpt match {
+              case Some(sv) =>
+                List(Keys.scalaVersion := sv)
+              case _ =>
+                List(Keys.autoScalaLibrary := false, Keys.crossPaths := false)
+            }
+          )
+          .settings(
+            target := base.getAbsoluteFile / "target" / svDirSuffix.dropWhile(_ == '-'),
+            crossTarget := Keys.target.value,
+            sourceDirectory := base.getAbsoluteFile / "src",
+            unmanagedBase := base.getAbsoluteFile / "lib",
+            inConfig(Compile)(makeSources(nonScalaDirSuffix, svDirSuffix)),
+            inConfig(Test)(makeSources(nonScalaDirSuffix, svDirSuffix)),
+            projectDependencies := projectDependenciesTask.value,
+            ProjectMatrixKeys.virtualAxes := axes,
+            ProjectMatrixKeys.projectMatrixBaseDirectory := base,
+          )
+          .settings(self.settings)
+          .configure(transforms: _*)
+
+        r -> r.process(p)
+      }): _*)
+    }
+
+  // backport of https://github.com/sbt/sbt/pull/5767
+  def projectDependenciesTask: Def.Initialize[Task[Seq[ModuleID]]] =
+    Def.task {
+      val orig = projectDependencies.value
+      val sbv = scalaBinaryVersion.value
+      val ref = thisProjectRef.value
+      val data = settingsData.value
+      val deps = buildDependencies.value
+      deps.classpath(ref) flatMap { dep =>
+        for {
+          depProjId <- (dep.project / projectID).get(data)
+          depSBV <- (dep.project / scalaBinaryVersion).get(data)
+          depCross <- (dep.project / crossVersion).get(data)
+        } yield {
+          depCross match {
+            case b: CrossVersion.Binary if VirtualAxis.isScala2Scala3Sandwich(sbv, depSBV) =>
+              depProjId
+                .withCrossVersion(CrossVersion.constant(depSBV))
+                .withConfigurations(dep.configuration)
+                .withExplicitArtifacts(Vector.empty)
+            case _ =>
+              depProjId.withConfigurations(dep.configuration).withExplicitArtifacts(Vector.empty)
+          }
+        }
+      }
+    }
+
+    override lazy val componentProjects: Seq[Project] = resolvedMappings.values.toList
+
+    private def resolveMatrixAggregate(
+      other: ProjectMatrix,
+      thisRow: ProjectRow,
+    ): ProjectReference = other.resolveMatch(thisRow)
+
+    private def resolveMatrixDependency(
+      dep: MatrixClasspathDep[ProjectMatrixReference],
+      thisRow: ProjectRow
+    ): ClasspathDep[ProjectReference] =
+      dep match {
+        case MatrixClasspathDependency(matrix0: LocalProjectMatrix, configuration) =>
+          val other = lookupMatrix(matrix0)
+          ClasspathDependency(other.resolveMatch(thisRow), configuration)
+      }
+
+    // resolve to the closest match for the given row
+    private[sbt] def resolveMatch(thatRow: ProjectRow): ProjectReference =
+      (rows.find(r => r.isMatch(thatRow)) orElse
+        rows.find(r => r.isSecondaryMatch(thatRow))) match {
+        case Some(r) => LocalProject(resolveProjectIds(r))
+        case _       => sys.error(s"no rows were found in $id matching $thatRow: $rows")
+      }
+
+    private def makeSources(dirSuffix: String, svDirSuffix: String): Setting[_] = {
+      unmanagedSourceDirectories ++= Seq(
+        scalaSource.value.getParentFile / s"scala${dirSuffix}",
+        scalaSource.value.getParentFile / s"scala$svDirSuffix",
+        javaSource.value.getParentFile / s"java${dirSuffix}"
+      )
+    }
+
+    override def withId(id: String): ProjectMatrix = copy(id = id)
+
+    override def in(dir: sbt.File): ProjectMatrix = copy(base = dir)
+
+    override def configs(cs: Configuration*): ProjectMatrix =
+      copy(configurations = configurations ++ cs)
+
+    override def aggregate(refs: ProjectMatrixReference*): ProjectMatrix =
+      copy(aggregate = (aggregate: Seq[ProjectMatrixReference]) ++ refs)
+
+    override def aggregate(refs: ProjectReference*)(implicit dummyImplicit: DummyImplicit): ProjectMatrix =
+      copy(nonMatrixAggregate = (nonMatrixAggregate: Seq[ProjectReference]) ++ refs)
+
+    override def dependsOn(deps: MatrixClasspathDep[ProjectMatrixReference]*): ProjectMatrix =
+      copy(dependencies = dependencies ++ deps)
+
+    override def dependsOn(deps: ClasspathDep[ProjectReference]*)(implicit dummyImplicit: DummyImplicit) =
+      copy(nonMatrixDependencies = nonMatrixDependencies ++ deps)
+
+    /** Appends settings to the current settings sequence for this project. */
+    override def settings(ss: Def.SettingsDefinition*): ProjectMatrix =
+      copy(settings = (settings: Seq[Def.Setting[_]]) ++ Def.settings(ss: _*))
+
+    override def enablePlugins(ns: Plugins*): ProjectMatrix =
+      setPlugins(ns.foldLeft(plugins)(Plugins.and))
+
+    override def disablePlugins(ps: AutoPlugin*): ProjectMatrix =
+      setPlugins(Plugins.and(plugins, Plugins.And(ps.map(p => Plugins.Exclude(p)).toList)))
+
+    override def configure(ts: (Project => Project)*): ProjectMatrix =
+      copy(transforms = transforms ++ ts)
+
+    def setPlugins(ns: Plugins): ProjectMatrix = copy(plugins = ns)
+
+    override def jvmPlatform(scalaVersions: Seq[String]): ProjectMatrix =
+      jvmPlatform(scalaVersions, Nil)
+    override def jvmPlatform(autoScalaLibrary: Boolean): ProjectMatrix =
+      jvmPlatform(autoScalaLibrary, Nil, Nil)
+    override def jvmPlatform(scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix =
+      jvmPlatform(true, scalaVersions, settings)
+    override def jvmPlatform(autoScalaLibrary: Boolean, scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix =
+      customRow(autoScalaLibrary, scalaVersions, Seq(VirtualAxis.jvm), { _.settings(settings) })
+    
+    override def jvmPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], settings: Seq[Setting[_]]): ProjectMatrix = 
+      customRow(true, scalaVersions, VirtualAxis.jvm +: axisValues, {_.settings(settings)})
+    
+    override def jvmPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], configure: Project => Project): ProjectMatrix = 
+      customRow(true, scalaVersions, VirtualAxis.jvm +: axisValues, configure)
+
+    override def jvm: ProjectFinder = new AxisBaseProjectFinder(Seq(VirtualAxis.jvm))
+
+    override def jsPlatform(scalaVersions: Seq[String]): ProjectMatrix =
+      jsPlatform(scalaVersions, Nil)
+
+    private def enableScalaJSPlugin(project: Project): Project = 
+      project.enablePlugins(scalajsPlugin(this.getClass.getClassLoader).getOrElse(
+        sys.error("""Scala.js plugin was not found. Add the sbt-scalajs plugin into project/plugins.sbt:
+                    |  addSbtPlugin("org.scala-js" % "sbt-scalajs" % "x.y.z")
+                    |""".stripMargin)
+      ))
+
+
+    override def jsPlatform(scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix =
+      customRow(true, scalaVersions, Seq(VirtualAxis.js),
+        project => enableScalaJSPlugin(project).settings(settings))
+    
+    override def jsPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], settings: Seq[Setting[_]]): ProjectMatrix =
+      customRow(true, scalaVersions, VirtualAxis.js +: axisValues,
+        project => enableScalaJSPlugin(project).settings(settings))
+    
+    override def jsPlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], configure: Project => Project): ProjectMatrix =
+      customRow(true, scalaVersions, VirtualAxis.js +: axisValues,
+        project => configure(enableScalaJSPlugin(project)))
+
+    override def defaultAxes(axes: VirtualAxis*): ProjectMatrix =
+      copy(defAxes = axes.toSeq)
+
+    def scalajsPlugin(classLoader: ClassLoader): Try[AutoPlugin] = {
+      import sbtprojectmatrix.ReflectionUtil._
+      withContextClassloader(classLoader) { loader =>
+        getSingletonObject[AutoPlugin](loader, "org.scalajs.sbtplugin.ScalaJSPlugin$")
+      }
+    }
+
+    override def js: ProjectFinder = new AxisBaseProjectFinder(Seq(VirtualAxis.js))
+
+    override def native: ProjectFinder = new AxisBaseProjectFinder(Seq(VirtualAxis.native))
+
+    override def nativePlatform(scalaVersions: Seq[String]): ProjectMatrix =
+      nativePlatform(scalaVersions, Nil)
+
+    private def enableScalaNativePlugin(project: Project): Project = 
+      project.enablePlugins(nativePlugin(this.getClass.getClassLoader).getOrElse(
+        sys.error("""Scala Native plugin was not found. Add the sbt-scala-native plugin into project/plugins.sbt:
+                    |  addSbtPlugin("org.scala-native" % "sbt-scala-native" % "x.y.z")
+                    |""".stripMargin)
+      ))
+
+
+    override def nativePlatform(scalaVersions: Seq[String], settings: Seq[Setting[_]]): ProjectMatrix =
+      customRow(true, scalaVersions, Seq(VirtualAxis.native), project => enableScalaNativePlugin(project).settings(settings))
+    
+    override def nativePlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], settings: Seq[Setting[_]]): ProjectMatrix =
+      customRow(true, scalaVersions, VirtualAxis.native +: axisValues, project => enableScalaNativePlugin(project).settings(settings))
+
+    override def nativePlatform(scalaVersions: Seq[String], axisValues: Seq[VirtualAxis], configure: Project => Project): ProjectMatrix =
+      customRow(true, scalaVersions, VirtualAxis.native +: axisValues, project => configure(enableScalaNativePlugin(project)))
+
+    def nativePlugin(classLoader: ClassLoader): Try[AutoPlugin] = {
+      import sbtprojectmatrix.ReflectionUtil._
+      withContextClassloader(classLoader) { loader =>
+        getSingletonObject[AutoPlugin](loader, "scala.scalanative.sbtplugin.ScalaNativePlugin$")
+      }
+    }
+
+    override def projectRefs: Seq[ProjectReference] =
+      componentProjects map { case p => (p: ProjectReference) }
+
+    override def filterProjects(axisValues: Seq[VirtualAxis]): Seq[Project] =
+      resolvedMappings.toSeq collect {
+        case (r, p) if axisValues.forall(v => r.axisValues.contains(v)) => p
+      }
+    override def filterProjects(autoScalaLibrary: Boolean, axisValues: Seq[VirtualAxis]): Seq[Project] =
+      resolvedMappings.toSeq collect {
+        case (r, p) if r.autoScalaLibrary == autoScalaLibrary && axisValues.forall(v => r.axisValues.contains(v)) => p
+      }
+
+    private final class AxisBaseProjectFinder(axisValues: Seq[VirtualAxis]) extends ProjectFinder {
+      def get: Seq[Project] = filterProjects(axisValues)
+      def apply(sv: String): Project =
+        filterProjects(true, axisValues ++ Seq(VirtualAxis.scalaABIVersion(sv))).headOption
+        .getOrElse(sys.error(s"project matching $axisValues and $sv was not found"))
+      def apply(autoScalaLibrary: Boolean): Project =
+        filterProjects(autoScalaLibrary, axisValues).headOption
+        .getOrElse(sys.error(s"project matching $axisValues and $autoScalaLibrary was not found"))
+    }
+
+    override def customRow(
+      scalaVersions: Seq[String],
+      axisValues: Seq[VirtualAxis],
+      settings: Seq[Setting[_]]
+    ): ProjectMatrix = customRow(true, scalaVersions, axisValues, { _.settings(settings) })
+
+    override def customRow(
+      autoScalaLibrary: Boolean,
+      axisValues: Seq[VirtualAxis],
+      settings: Seq[Setting[_]]
+    ): ProjectMatrix = customRow(autoScalaLibrary, Nil, axisValues, { _.settings(settings) })
+
+    override def customRow(
+      scalaVersions: Seq[String],
+      axisValues: Seq[VirtualAxis],
+      process: Project => Project
+    ): ProjectMatrix = customRow(true, scalaVersions, axisValues, process)
+
+    override def customRow(
+      autoScalaLibrary: Boolean,
+      scalaVersions: Seq[String],
+      axisValues: Seq[VirtualAxis],
+      process: Project => Project
+    ): ProjectMatrix =
+      if (autoScalaLibrary) {
+        scalaVersions.foldLeft(this: ProjectMatrix) { (acc, sv) =>
+          acc.customRow(autoScalaLibrary, axisValues ++ Seq(VirtualAxis.scalaABIVersion(sv)), process)
+        }
+      } else {
+        customRow(autoScalaLibrary, axisValues ++ Seq(VirtualAxis.jvm), process)
+      }
+
+    override def customRow(
+      autoScalaLibrary: Boolean,
+      axisValues: Seq[VirtualAxis],
+      process: Project => Project
+    ): ProjectMatrix = {
+      val newRow: ProjectRow = new ProjectRow(autoScalaLibrary, axisValues, process)
+      copy(rows = this.rows :+ newRow)
+    }
+
+    override def finder(axisValues: VirtualAxis*): ProjectFinder =
+      new AxisBaseProjectFinder(axisValues.toSeq)
+
+    override def allProjects(): Seq[(Project, Seq[VirtualAxis])] =
+      resolvedMappings.map { case(row, project) =>
+        project -> row.axisValues
+      }.toSeq
+
+    def copy(
+        id: String = id,
+        base: sbt.File = base,
+        scalaVersions: Seq[String] = scalaVersions,
+        rows: Seq[ProjectRow] = rows,
+        aggregate: Seq[ProjectMatrixReference] = aggregate,
+        nonMatrixAggregate: Seq[ProjectReference] = nonMatrixAggregate,
+        dependencies: Seq[MatrixClasspathDep[ProjectMatrixReference]] = dependencies,
+        nonMatrixDependencies: Seq[ClasspathDep[ProjectReference]] = nonMatrixDependencies,
+        settings: Seq[Setting[_]] = settings,
+        configurations: Seq[Configuration] = configurations,
+        plugins: Plugins = plugins,
+        transforms: Seq[Project => Project] = transforms,
+        defAxes: Seq[VirtualAxis] = defAxes,
+    ): ProjectMatrix = {
+      val matrix = unresolved(
+        id,
+        base,
+        scalaVersions,
+        rows,
+        aggregate,
+        nonMatrixAggregate,
+        dependencies,
+        nonMatrixDependencies,
+        settings,
+        configurations,
+        plugins,
+        transforms,
+        defAxes,
+      )
+      allMatrices(id) = matrix
+      matrix
+    }
+  }
+
+  // called by macro
+  def apply(id: String, base: sbt.File): ProjectMatrix = {
+    val defaultDefAxes = Seq(VirtualAxis.jvm, VirtualAxis.scalaABIVersion("2.13.3"))
+    val matrix = unresolved(id, base, Nil, Nil, Nil, Nil, Nil, Nil, Nil, Nil, Plugins.Empty, Nil, defaultDefAxes)
+    allMatrices(id) = matrix
+    matrix
+  }
+
+  private[sbt] def unresolved(
+      id: String,
+      base: sbt.File,
+      scalaVersions: Seq[String],
+      rows: Seq[ProjectRow],
+      aggregate: Seq[ProjectMatrixReference],
+      nonMatrixAggregate: Seq[ProjectReference],
+      dependencies: Seq[MatrixClasspathDep[ProjectMatrixReference]],
+      nonMatrixDependencies: Seq[ClasspathDep[ProjectReference]],
+      settings: Seq[Def.Setting[_]],
+      configurations: Seq[Configuration],
+      plugins: Plugins,
+      transforms: Seq[Project => Project],
+      defAxes: Seq[VirtualAxis],
+  ): ProjectMatrix =
+    new ProjectMatrixDef(
+      id,
+      base,
+      scalaVersions,
+      rows,
+      aggregate,
+      nonMatrixAggregate,
+      dependencies,
+      nonMatrixDependencies,
+      settings,
+      configurations,
+      plugins,
+      transforms,
+      defAxes,
+    )
+
+  def lookupMatrix(local: LocalProjectMatrix): ProjectMatrix = {
+    allMatrices.getOrElse(local.id, sys.error(s"${local.id} was not found"))
+  }
+
+  implicit def projectMatrixToLocalProjectMatrix(m: ProjectMatrix): LocalProjectMatrix =
+    LocalProjectMatrix(m.id)
+
+  import scala.reflect.macros._
+
+  def projectMatrixMacroImpl(c: blackbox.Context): c.Expr[ProjectMatrix] = {
+    import c.universe._
+    val enclosingValName = std.KeyMacro.definingValName(
+      c,
+      methodName =>
+        s"""$methodName must be directly assigned to a val, such as `val x = $methodName`. Alternatively, you can use `sbt.ProjectMatrix.apply`"""
+    )
+    val name = c.Expr[String](Literal(Constant(enclosingValName)))
+    reify { ProjectMatrix(name.splice, new sbt.File(name.splice)) }
+  }
+}
diff --git a/src/main/scala/sbt/internal/ProjectMatrixReference.scala b/src/main/scala/sbt/internal/ProjectMatrixReference.scala
new file mode 100644
index 000000000..5ed710cda
--- /dev/null
+++ b/src/main/scala/sbt/internal/ProjectMatrixReference.scala
@@ -0,0 +1,8 @@
+package sbt
+package internal
+
+/** Identifies a project matrix. */
+sealed trait ProjectMatrixReference
+
+/** Identifies a project in the current build context. */
+final case class LocalProjectMatrix(id: String) extends ProjectMatrixReference
diff --git a/src/main/scala/sbtprojectmatrix/ProjectMatrixPlugin.scala b/src/main/scala/sbtprojectmatrix/ProjectMatrixPlugin.scala
new file mode 100644
index 000000000..54d883ab2
--- /dev/null
+++ b/src/main/scala/sbtprojectmatrix/ProjectMatrixPlugin.scala
@@ -0,0 +1,31 @@
+package sbtprojectmatrix
+
+import sbt._
+import internal._
+import java.util.concurrent.atomic.AtomicBoolean
+import scala.language.experimental.macros
+
+trait ProjectMatrixKeys {
+    val virtualAxes = settingKey[Seq[VirtualAxis]]("Virtual axes for the project")
+    val projectMatrixBaseDirectory = settingKey[File]("Base directory of the current project matrix")
+}
+
+object ProjectMatrixKeys extends ProjectMatrixKeys
+
+object ProjectMatrixPlugin extends AutoPlugin {
+  override val requires = sbt.plugins.CorePlugin
+  override val trigger = allRequirements
+  object autoImport extends ProjectMatrixKeys {
+    def projectMatrix: ProjectMatrix = macro ProjectMatrix.projectMatrixMacroImpl
+
+    implicit def matrixClasspathDependency[T](
+      m: T
+    )(implicit ev: T => ProjectMatrixReference): ProjectMatrix.MatrixClasspathDependency =
+      ProjectMatrix.MatrixClasspathDependency(m, None)
+
+    implicit def matrixReferenceSyntax[T](
+      m: T
+    )(implicit ev: T => ProjectMatrixReference): ProjectMatrix.ProjectMatrixReferenceSyntax =
+      new ProjectMatrix.ProjectMatrixReferenceSyntax(m)
+  }
+}
diff --git a/src/main/scala/sbtprojectmatrix/ReflectionUtil.scala b/src/main/scala/sbtprojectmatrix/ReflectionUtil.scala
new file mode 100644
index 000000000..77081ec6f
--- /dev/null
+++ b/src/main/scala/sbtprojectmatrix/ReflectionUtil.scala
@@ -0,0 +1,36 @@
+package sbtprojectmatrix
+
+import java.lang.reflect.InvocationTargetException
+import scala.reflect.ClassTag
+import scala.util.Try
+
+object ReflectionUtil {
+  def getSingletonObject[A: ClassTag](classLoader: ClassLoader, className: String): Try[A] =
+    Try {
+      val clazz = classLoader.loadClass(className)
+      val t = implicitly[ClassTag[A]].runtimeClass
+      Option(clazz.getField("MODULE$").get(null)) match {
+        case None                        => throw new ClassNotFoundException(s"Unable to find $className using classloader: $classLoader")
+        case Some(c) if !t.isInstance(c) => throw new ClassCastException(s"${clazz.getName} is not a subtype of $t")
+        case Some(c: A)                  => c
+      }
+    }
+    .recover {
+      case i: InvocationTargetException if i.getTargetException != null => throw i.getTargetException
+    }
+
+  def objectExists(classLoader: ClassLoader, className: String): Boolean =
+    try {
+      classLoader.loadClass(className).getField("MODULE$").get(null) != null
+    } catch {
+      case _: Throwable => false
+    }
+
+  def withContextClassloader[A](loader: ClassLoader)(body: ClassLoader => A): A = {
+    val current = Thread.currentThread().getContextClassLoader
+    try {
+      Thread.currentThread().setContextClassLoader(loader)
+      body(loader)
+    } finally Thread.currentThread().setContextClassLoader(current)
+  }
+}
diff --git a/src/sbt-test/projectMatrix/custom/app/src/main/scala/B.scala b/src/sbt-test/projectMatrix/custom/app/src/main/scala/B.scala
new file mode 100644
index 000000000..0af0d7579
--- /dev/null
+++ b/src/sbt-test/projectMatrix/custom/app/src/main/scala/B.scala
@@ -0,0 +1,5 @@
+package example
+
+object B {
+  def b: Int = A.a
+}
diff --git a/src/sbt-test/projectMatrix/custom/build.sbt b/src/sbt-test/projectMatrix/custom/build.sbt
new file mode 100644
index 000000000..10b14e863
--- /dev/null
+++ b/src/sbt-test/projectMatrix/custom/build.sbt
@@ -0,0 +1,46 @@
+ThisBuild / organization := "com.example"
+ThisBuild / version := "0.1.0-SNAPSHOT"
+ThisBuild / publishMavenStyle := true
+
+ThisBuild / ivyPaths := {
+  val base = (ThisBuild / baseDirectory).value
+  IvyPaths(base, Some(base / "ivy-cache"))
+}
+publish / skip := true
+
+lazy val config12 = ConfigAxis("Config1_2", "config1.2")
+lazy val config13 = ConfigAxis("Config1_3", "config1.3")
+
+lazy val scala212 = "2.12.10"
+lazy val scala211 = "2.11.12"
+
+lazy val core = (projectMatrix in file("core"))
+  .jvmPlatform(scalaVersions = Seq(scala212, scala211))
+
+lazy val app = (projectMatrix in file("app"))
+  .dependsOn(core)
+  .settings(
+    name := "app",
+    ivyPaths := (ThisBuild / ivyPaths).value
+  )
+  .customRow(
+    scalaVersions = Seq(scala212, scala211),
+    axisValues = Seq(config12, VirtualAxis.jvm),
+    _.settings(
+      moduleName := name.value + "_config1.2",
+      libraryDependencies += "com.typesafe" % "config" % "1.2.1"
+    )
+  )
+  .customRow(
+    scalaVersions = Seq(scala212, scala211),
+    axisValues = Seq(config13, VirtualAxis.jvm),
+    _.settings(
+      moduleName := name.value + "_config1.3",
+      libraryDependencies += "com.typesafe" % "config" % "1.3.3"
+    )
+  )
+
+lazy val appConfig12_212 = app.finder(config13, VirtualAxis.jvm)(scala212)
+  .settings(
+    publishMavenStyle := true
+  )
diff --git a/src/sbt-test/projectMatrix/custom/core/src/main/scala/A.scala b/src/sbt-test/projectMatrix/custom/core/src/main/scala/A.scala
new file mode 100644
index 000000000..e62671081
--- /dev/null
+++ b/src/sbt-test/projectMatrix/custom/core/src/main/scala/A.scala
@@ -0,0 +1,5 @@
+package example
+
+object A {
+  def a: Int = 1
+}
diff --git a/src/sbt-test/projectMatrix/custom/project/ConfigAxis.scala b/src/sbt-test/projectMatrix/custom/project/ConfigAxis.scala
new file mode 100644
index 000000000..b1124c60e
--- /dev/null
+++ b/src/sbt-test/projectMatrix/custom/project/ConfigAxis.scala
@@ -0,0 +1,5 @@
+import sbt._
+
+case class ConfigAxis(idSuffix: String, directorySuffix: String) extends VirtualAxis.WeakAxis {
+
+}
diff --git a/src/sbt-test/projectMatrix/custom/project/plugins.sbt b/src/sbt-test/projectMatrix/custom/project/plugins.sbt
new file mode 100644
index 000000000..4e80bbafc
--- /dev/null
+++ b/src/sbt-test/projectMatrix/custom/project/plugins.sbt
@@ -0,0 +1,5 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
diff --git a/src/sbt-test/projectMatrix/custom/test b/src/sbt-test/projectMatrix/custom/test
new file mode 100644
index 000000000..c92f20c49
--- /dev/null
+++ b/src/sbt-test/projectMatrix/custom/test
@@ -0,0 +1,6 @@
+> publishLocal
+
+$ exists ivy-cache/local/com.example/app_config1.2_2.11/0.1.0-SNAPSHOT/poms/app_config1.2_2.11.pom
+$ exists ivy-cache/local/com.example/app_config1.2_2.12/0.1.0-SNAPSHOT/poms/app_config1.2_2.12.pom
+$ exists ivy-cache/local/com.example/app_config1.3_2.11/0.1.0-SNAPSHOT/poms/app_config1.3_2.11.pom
+$ exists ivy-cache/local/com.example/app_config1.3_2.12/0.1.0-SNAPSHOT/poms/app_config1.3_2.12.pom
diff --git a/src/sbt-test/projectMatrix/finder/build.sbt b/src/sbt-test/projectMatrix/finder/build.sbt
new file mode 100644
index 000000000..a4e8632c2
--- /dev/null
+++ b/src/sbt-test/projectMatrix/finder/build.sbt
@@ -0,0 +1,45 @@
+lazy val scala213 = "2.13.3"
+lazy val scala212 = "2.12.12"
+lazy val check = taskKey[Unit]("")
+
+
+lazy val config12 = ConfigAxis("Config1_2", "config1.2")
+lazy val config13 = ConfigAxis("Config1_3", "config1.3")
+
+lazy val root = (project in file("."))
+  .aggregate((core.projectRefs ++ custom.projectRefs):_*)
+
+lazy val core = (projectMatrix in file("core"))
+  .jvmPlatform(scalaVersions = Seq(scala213, scala212))
+  .jsPlatform(scalaVersions = Seq(scala212))
+
+lazy val custom =
+  (projectMatrix in file("custom"))
+  .customRow(
+    scalaVersions = Seq(scala212),
+    axisValues = Seq(config13, VirtualAxis.jvm),
+    _.settings()
+  )
+
+check := {
+  val coreResults: Map[Project, Set[VirtualAxis]] = core.allProjects().toMap.mapValues(_.toSet)
+  val customResults: Map[Project, Set[VirtualAxis]] = custom.allProjects().toMap.mapValues(_.toSet)
+
+  val isJvm = VirtualAxis.jvm
+  val isJs = VirtualAxis.js
+  val is213 = VirtualAxis.scalaPartialVersion(scala213)
+  val is212 = VirtualAxis.scalaPartialVersion(scala212)
+
+  val coreSubProjects = Set(
+    core.jvm(scala213), core.jvm(scala212),
+    core.js(scala212)
+  )
+
+  assert(coreResults.keySet == coreSubProjects)
+  assert(coreResults(core.jvm(scala213)) == Set(isJvm, is213))
+  assert(coreResults(core.jvm(scala212)) == Set(isJvm, is212))
+  assert(coreResults(core.js(scala212)) == Set(isJs, is212))
+
+  assert(customResults.keySet == Set(custom.jvm(scala212)))
+  assert(customResults(custom.jvm(scala212)) == Set(isJvm, is212, config13))
+}
diff --git a/src/sbt-test/projectMatrix/finder/project/ConfigAxis.scala b/src/sbt-test/projectMatrix/finder/project/ConfigAxis.scala
new file mode 100644
index 000000000..bdabcb757
--- /dev/null
+++ b/src/sbt-test/projectMatrix/finder/project/ConfigAxis.scala
@@ -0,0 +1,3 @@
+import sbt._
+
+case class ConfigAxis(idSuffix: String, directorySuffix: String) extends VirtualAxis.WeakAxis
diff --git a/src/sbt-test/projectMatrix/finder/project/plugins.sbt b/src/sbt-test/projectMatrix/finder/project/plugins.sbt
new file mode 100644
index 000000000..60a69f1df
--- /dev/null
+++ b/src/sbt-test/projectMatrix/finder/project/plugins.sbt
@@ -0,0 +1,7 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
+
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.3.0")
diff --git a/src/sbt-test/projectMatrix/finder/test b/src/sbt-test/projectMatrix/finder/test
new file mode 100644
index 000000000..e3bd83da1
--- /dev/null
+++ b/src/sbt-test/projectMatrix/finder/test
@@ -0,0 +1,2 @@
+> compile
+> check
diff --git a/src/sbt-test/projectMatrix/java/app/src/main/java-config1.2-jvm/com/config/MyClass.java b/src/sbt-test/projectMatrix/java/app/src/main/java-config1.2-jvm/com/config/MyClass.java
new file mode 100644
index 000000000..b714ca27b
--- /dev/null
+++ b/src/sbt-test/projectMatrix/java/app/src/main/java-config1.2-jvm/com/config/MyClass.java
@@ -0,0 +1,9 @@
+package com.config;
+
+public class MyClass {
+
+    public static String configValue() {
+        return "1.2";
+    }
+  
+}
diff --git a/src/sbt-test/projectMatrix/java/app/src/main/java-config1.3-jvm/com/config/MyClass.java b/src/sbt-test/projectMatrix/java/app/src/main/java-config1.3-jvm/com/config/MyClass.java
new file mode 100644
index 000000000..2c4800d95
--- /dev/null
+++ b/src/sbt-test/projectMatrix/java/app/src/main/java-config1.3-jvm/com/config/MyClass.java
@@ -0,0 +1,9 @@
+package com.config;
+
+public class MyClass {
+
+    public static String configValue() {
+        return "1.3";
+    }
+  
+}
diff --git a/src/sbt-test/projectMatrix/java/app/src/main/scala/com/config/Main.scala b/src/sbt-test/projectMatrix/java/app/src/main/scala/com/config/Main.scala
new file mode 100644
index 000000000..864de72cd
--- /dev/null
+++ b/src/sbt-test/projectMatrix/java/app/src/main/scala/com/config/Main.scala
@@ -0,0 +1,5 @@
+package com.config
+
+object Main extends App {
+    println(s"Version: ${MyClass.configValue()}")
+}
diff --git a/src/sbt-test/projectMatrix/java/build.sbt b/src/sbt-test/projectMatrix/java/build.sbt
new file mode 100644
index 000000000..d4532995a
--- /dev/null
+++ b/src/sbt-test/projectMatrix/java/build.sbt
@@ -0,0 +1,41 @@
+ThisBuild / organization := "com.example"
+ThisBuild / version := "0.1.0-SNAPSHOT"
+ThisBuild / publishMavenStyle := true
+
+ThisBuild / ivyPaths := {
+  val base = (ThisBuild / baseDirectory).value
+  IvyPaths(base, Some(base / "ivy-cache"))
+}
+publish / skip := true
+
+lazy val config12 = ConfigAxis("Config1_2", "-config1.2")
+lazy val config13 = ConfigAxis("Config1_3", "-config1.3")
+
+lazy val scala212 = "2.12.10"
+
+lazy val app = (projectMatrix in file("app"))
+  .settings(
+    name := "app",
+    ivyPaths := (ThisBuild / ivyPaths).value
+  )
+  .customRow(
+    scalaVersions = Seq(scala212),
+    axisValues = Seq(config12, VirtualAxis.jvm),
+    _.settings(
+      moduleName := name.value + "_config1.2",
+      libraryDependencies += "com.typesafe" % "config" % "1.2.1"
+    )
+  )
+  .customRow(
+    scalaVersions = Seq(scala212),
+    axisValues = Seq(config13, VirtualAxis.jvm),
+    _.settings(
+      moduleName := name.value + "_config1.3",
+      libraryDependencies += "com.typesafe" % "config" % "1.3.3"
+    )
+  )
+
+lazy val appConfig12_212 = app.finder(config13, VirtualAxis.jvm)(scala212)
+  .settings(
+    publishMavenStyle := true
+  )
diff --git a/src/sbt-test/projectMatrix/java/project/ConfigAxis.scala b/src/sbt-test/projectMatrix/java/project/ConfigAxis.scala
new file mode 100644
index 000000000..b1124c60e
--- /dev/null
+++ b/src/sbt-test/projectMatrix/java/project/ConfigAxis.scala
@@ -0,0 +1,5 @@
+import sbt._
+
+case class ConfigAxis(idSuffix: String, directorySuffix: String) extends VirtualAxis.WeakAxis {
+
+}
diff --git a/src/sbt-test/projectMatrix/java/project/plugins.sbt b/src/sbt-test/projectMatrix/java/project/plugins.sbt
new file mode 100644
index 000000000..4e80bbafc
--- /dev/null
+++ b/src/sbt-test/projectMatrix/java/project/plugins.sbt
@@ -0,0 +1,5 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
diff --git a/src/sbt-test/projectMatrix/java/test b/src/sbt-test/projectMatrix/java/test
new file mode 100644
index 000000000..964c0eac1
--- /dev/null
+++ b/src/sbt-test/projectMatrix/java/test
@@ -0,0 +1,4 @@
+> publishLocal
+
+$ exists ivy-cache/local/com.example/app_config1.2_2.12/0.1.0-SNAPSHOT/poms/app_config1.2_2.12.pom
+$ exists ivy-cache/local/com.example/app_config1.3_2.12/0.1.0-SNAPSHOT/poms/app_config1.3_2.12.pom
diff --git a/src/sbt-test/projectMatrix/js/build.sbt b/src/sbt-test/projectMatrix/js/build.sbt
new file mode 100644
index 000000000..9300a02ef
--- /dev/null
+++ b/src/sbt-test/projectMatrix/js/build.sbt
@@ -0,0 +1,17 @@
+// lazy val root = (project in file("."))
+//   .aggregate(core.projectRefs ++ app.projectRefs: _*)
+//   .settings(
+//   )
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    name := "core"
+  )
+  .jsPlatform(scalaVersions = Seq("2.12.8", "2.11.12"))
+
+lazy val app = (projectMatrix in file("app"))
+  .dependsOn(core)
+  .settings(
+    name := "app"
+  )
+  .jsPlatform(scalaVersions = Seq("2.12.8"))
diff --git a/src/sbt-test/projectMatrix/js/core/src/main/scala/Core.scala b/src/sbt-test/projectMatrix/js/core/src/main/scala/Core.scala
new file mode 100644
index 000000000..274e01225
--- /dev/null
+++ b/src/sbt-test/projectMatrix/js/core/src/main/scala/Core.scala
@@ -0,0 +1,6 @@
+package a
+
+class Core {
+}
+
+object Core extends Core
diff --git a/src/sbt-test/projectMatrix/js/project/plugins.sbt b/src/sbt-test/projectMatrix/js/project/plugins.sbt
new file mode 100644
index 000000000..70858c7d8
--- /dev/null
+++ b/src/sbt-test/projectMatrix/js/project/plugins.sbt
@@ -0,0 +1,6 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.27")
diff --git a/src/sbt-test/projectMatrix/js/test b/src/sbt-test/projectMatrix/js/test
new file mode 100644
index 000000000..553c6bf3a
--- /dev/null
+++ b/src/sbt-test/projectMatrix/js/test
@@ -0,0 +1,5 @@
+> fastOptJS
+
+$ exists app/target/js-2.12/app-fastopt.js
+$ exists core/target/js-2.12/core-fastopt.js
+$ exists core/target/js-2.11/core-fastopt.js
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/bar-app/D.scala b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/bar-app/D.scala
new file mode 100644
index 000000000..b937ae06c
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/bar-app/D.scala
@@ -0,0 +1,5 @@
+package example
+
+object D {
+  val x = C.x
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/bar-core/C.scala b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/bar-core/C.scala
new file mode 100644
index 000000000..4d4fcc6df
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/bar-core/C.scala
@@ -0,0 +1,5 @@
+package example
+
+object C {
+  val x = 1
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/baz-app/F.scala b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/baz-app/F.scala
new file mode 100644
index 000000000..5035ba457
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/baz-app/F.scala
@@ -0,0 +1,5 @@
+package example
+
+object F {
+  val x = E.x
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/baz-core/E.scala b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/baz-core/E.scala
new file mode 100644
index 000000000..cdac7bd76
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/baz-core/E.scala
@@ -0,0 +1,5 @@
+package example
+
+object E {
+  val x = 1
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/build.sbt b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/build.sbt
new file mode 100644
index 000000000..825f5215c
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/build.sbt
@@ -0,0 +1,57 @@
+lazy val check = taskKey[Unit]("")
+lazy val scala3M1 = "3.0.0-M1"
+lazy val scala3M2 = "3.0.0-M2"
+lazy val scala213 = "2.13.4"
+
+lazy val fooApp = (projectMatrix in file("foo-app"))
+  .dependsOn(fooCore)
+  .settings(
+    name := "foo app",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala3M1, scala3M2))
+
+lazy val fooApp3 = fooApp.jvm(scala3M1)
+  .settings(
+    test := { () },
+  )
+
+lazy val fooCore = (projectMatrix in file("foo-core"))
+  .settings(
+    name := "foo core",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213, "2.12.12"))
+
+lazy val barApp = (projectMatrix in file("bar-app"))
+  .dependsOn(barCore)
+  .settings(
+    name := "bar app",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213))
+
+lazy val barCore = (projectMatrix in file("bar-core"))
+  .settings(
+    name := "bar core",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala3M2))
+
+// choose 2.13 when bazCore offers both 2.13 and Dotty
+lazy val bazApp = (projectMatrix in file("baz-app"))
+  .dependsOn(bazCore)
+  .settings(
+    name := "baz app",
+    check := {
+      val cp = (Compile / fullClasspath).value
+        .map(_.data.getName)
+
+      assert(cp.contains("baz-core_2.13-0.1.0-SNAPSHOT.jar"), s"$cp")
+      assert(!cp.contains("baz-core_3.0.0-M1-0.1.0-SNAPSHOT.jar"), s"$cp")
+    },
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213))
+
+lazy val bazCore = (projectMatrix in file("baz-core"))
+  .settings(
+    name := "baz core",
+    exportJars := true,
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213, scala3M1))
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/foo-app/B.scala b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/foo-app/B.scala
new file mode 100644
index 000000000..ed82c07d1
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/foo-app/B.scala
@@ -0,0 +1,5 @@
+package example
+
+object B {
+  val x = A.x
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/foo-core/A.scala b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/foo-core/A.scala
new file mode 100644
index 000000000..be4b82a9f
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/foo-core/A.scala
@@ -0,0 +1,5 @@
+package example
+
+object A {
+  val x = 1
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/project/build.properties b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/project/build.properties
new file mode 100644
index 000000000..c19c768d6
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/project/build.properties
@@ -0,0 +1 @@
+sbt.version=1.4.2
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/project/plugins.sbt b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/project/plugins.sbt
new file mode 100644
index 000000000..2db30a892
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/project/plugins.sbt
@@ -0,0 +1,6 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.4.5")
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/test b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/test
new file mode 100644
index 000000000..18ed59f1b
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich-sbt-1.3/test
@@ -0,0 +1,7 @@
+> projects
+
+> fooApp3_0_0_M1/compile
+
+> barApp/compile
+
+> bazApp/check
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/bar-app/D.scala b/src/sbt-test/projectMatrix/jvm-sandwich/bar-app/D.scala
new file mode 100644
index 000000000..b937ae06c
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/bar-app/D.scala
@@ -0,0 +1,5 @@
+package example
+
+object D {
+  val x = C.x
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/bar-core/C.scala b/src/sbt-test/projectMatrix/jvm-sandwich/bar-core/C.scala
new file mode 100644
index 000000000..4d4fcc6df
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/bar-core/C.scala
@@ -0,0 +1,5 @@
+package example
+
+object C {
+  val x = 1
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/baz-app/F.scala b/src/sbt-test/projectMatrix/jvm-sandwich/baz-app/F.scala
new file mode 100644
index 000000000..5035ba457
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/baz-app/F.scala
@@ -0,0 +1,5 @@
+package example
+
+object F {
+  val x = E.x
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/baz-core/E.scala b/src/sbt-test/projectMatrix/jvm-sandwich/baz-core/E.scala
new file mode 100644
index 000000000..cdac7bd76
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/baz-core/E.scala
@@ -0,0 +1,5 @@
+package example
+
+object E {
+  val x = 1
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/build.sbt b/src/sbt-test/projectMatrix/jvm-sandwich/build.sbt
new file mode 100644
index 000000000..98c3f574a
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/build.sbt
@@ -0,0 +1,54 @@
+lazy val check = taskKey[Unit]("")
+lazy val scala3M1 = "3.0.0-M1"
+lazy val scala3M2 = "3.0.0-M2"
+lazy val scala213 = "2.13.4"
+
+lazy val fooApp = (projectMatrix in file("foo-app"))
+  .dependsOn(fooCore)
+  .settings(
+    name := "foo app",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala3M1, scala3M2))
+
+lazy val fooCore = (projectMatrix in file("foo-core"))
+  .settings(
+    name := "foo core",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213, "2.12.12"))
+
+lazy val barApp = (projectMatrix in file("bar-app"))
+  .dependsOn(barCore)
+  .settings(
+    name := "bar app",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213))
+
+lazy val barCore = (projectMatrix in file("bar-core"))
+  .settings(
+    name := "bar core",
+  )
+  .jvmPlatform(scalaVersions = Seq(scala3M1))
+
+// choose 2.13 when bazCore offers both 2.13 and Dotty
+lazy val bazApp = (projectMatrix in file("baz-app"))
+  .dependsOn(bazCore)
+  .settings(
+    name := "baz app",
+    check := {
+      val cp = (Compile / fullClasspath).value
+        .map(_.data.getName)
+
+      streams.value.log.info(cp.toString)
+      assert(cp.contains("baz-core_2.13-0.1.0-SNAPSHOT.jar"), s"$cp")
+      assert(!cp.contains("baz-core_3.0.0-M1-0.1.0-SNAPSHOT.jar"), s"$cp")
+      assert(projectMatrixBaseDirectory.value == file("baz-app"))
+    },
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213))
+
+lazy val bazCore = (projectMatrix in file("baz-core"))
+  .settings(
+    name := "baz core",
+    exportJars := true,
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213, scala3M1, scala3M2))
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/foo-app/B.scala b/src/sbt-test/projectMatrix/jvm-sandwich/foo-app/B.scala
new file mode 100644
index 000000000..ed82c07d1
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/foo-app/B.scala
@@ -0,0 +1,5 @@
+package example
+
+object B {
+  val x = A.x
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/foo-core/A.scala b/src/sbt-test/projectMatrix/jvm-sandwich/foo-core/A.scala
new file mode 100644
index 000000000..be4b82a9f
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/foo-core/A.scala
@@ -0,0 +1,5 @@
+package example
+
+object A {
+  val x = 1
+}
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/project/build.properties b/src/sbt-test/projectMatrix/jvm-sandwich/project/build.properties
new file mode 100644
index 000000000..c19c768d6
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/project/build.properties
@@ -0,0 +1 @@
+sbt.version=1.4.2
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/project/plugins.sbt b/src/sbt-test/projectMatrix/jvm-sandwich/project/plugins.sbt
new file mode 100644
index 000000000..2db30a892
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/project/plugins.sbt
@@ -0,0 +1,6 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.4.5")
diff --git a/src/sbt-test/projectMatrix/jvm-sandwich/test b/src/sbt-test/projectMatrix/jvm-sandwich/test
new file mode 100644
index 000000000..18ed59f1b
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-sandwich/test
@@ -0,0 +1,7 @@
+> projects
+
+> fooApp3_0_0_M1/compile
+
+> barApp/compile
+
+> bazApp/check
diff --git a/src/sbt-test/projectMatrix/jvm-with-project-axes/build.sbt b/src/sbt-test/projectMatrix/jvm-with-project-axes/build.sbt
new file mode 100644
index 000000000..4a7e5f31b
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-project-axes/build.sbt
@@ -0,0 +1,53 @@
+import sbt.internal.ProjectMatrix
+ThisBuild / organization := "com.example"
+ThisBuild / version := "0.1.0-SNAPSHOT"
+ThisBuild / publishMavenStyle := true
+
+ThisBuild / ivyPaths := {
+  val base = (ThisBuild / baseDirectory).value
+  IvyPaths(base, Some(base / "ivy-cache"))
+}
+publish / skip := true
+
+lazy val scala212 = "2.12.10"
+
+lazy val check = taskKey[Unit]("")
+
+lazy val config12 = ConfigAxis("Config1_2", "-config1.2")
+lazy val config13 = ConfigAxis("Config1_3", "-config1.3")
+
+check := {
+  val app12 = app.finder(config12).apply(autoScalaLibrary = false)
+  assert(app12.id == "appConfig1_2", s"app12.id is ${app12.id}")
+  val app13 = app.finder(config13).apply(autoScalaLibrary = false)
+  assert(app13.id == "appConfig1_3", s"app13.id is ${app13.id}")
+}
+
+lazy val app: ProjectMatrix = (projectMatrix in file("app"))
+  .settings(
+    name := "app",
+    ivyPaths := (ThisBuild / ivyPaths).value
+  )
+  .aggregate(domain)
+  .dependsOn(domain)
+  .customRow(
+    autoScalaLibrary = false,
+    scalaVersions = Seq(scala212),
+    axisValues = Seq(config12, VirtualAxis.jvm),
+    _.settings(
+      libraryDependencies += "com.typesafe" % "config" % "1.2.1"
+    )
+  )
+  .customRow(
+    autoScalaLibrary = false,
+    scalaVersions = Seq(scala212),
+    axisValues = Seq(config13, VirtualAxis.jvm),
+    _.settings(
+      libraryDependencies += "com.typesafe" % "config" % "1.3.3"
+    )
+  )
+
+lazy val domain = (project in file("domain"))
+  .settings(
+    scalaVersion := scala212
+  )
diff --git a/src/sbt-test/projectMatrix/jvm-with-project-axes/domain/src/main/scala/DataType.scala b/src/sbt-test/projectMatrix/jvm-with-project-axes/domain/src/main/scala/DataType.scala
new file mode 100644
index 000000000..499a83d60
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-project-axes/domain/src/main/scala/DataType.scala
@@ -0,0 +1,3 @@
+package a
+
+case class DataType()
diff --git a/src/sbt-test/projectMatrix/jvm-with-project-axes/project/ConfigAxis.scala b/src/sbt-test/projectMatrix/jvm-with-project-axes/project/ConfigAxis.scala
new file mode 100644
index 000000000..bdabcb757
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-project-axes/project/ConfigAxis.scala
@@ -0,0 +1,3 @@
+import sbt._
+
+case class ConfigAxis(idSuffix: String, directorySuffix: String) extends VirtualAxis.WeakAxis
diff --git a/src/sbt-test/projectMatrix/jvm-with-project-axes/project/plugins.sbt b/src/sbt-test/projectMatrix/jvm-with-project-axes/project/plugins.sbt
new file mode 100644
index 000000000..4e80bbafc
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-project-axes/project/plugins.sbt
@@ -0,0 +1,5 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
diff --git a/src/sbt-test/projectMatrix/jvm-with-project-axes/test b/src/sbt-test/projectMatrix/jvm-with-project-axes/test
new file mode 100644
index 000000000..29c0480b3
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-project-axes/test
@@ -0,0 +1,5 @@
+> compile
+
+$ exists domain/target/scala-2.12/classes/a/DataType.class
+
+> check
diff --git a/src/sbt-test/projectMatrix/jvm-with-scoping/app/src/main/scala/Main.scala b/src/sbt-test/projectMatrix/jvm-with-scoping/app/src/main/scala/Main.scala
new file mode 100644
index 000000000..510a46894
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-scoping/app/src/main/scala/Main.scala
@@ -0,0 +1,5 @@
+package a
+
+object Main extends App {
+  val core = Core
+}
diff --git a/src/sbt-test/projectMatrix/jvm-with-scoping/build.sbt b/src/sbt-test/projectMatrix/jvm-with-scoping/build.sbt
new file mode 100644
index 000000000..998141af4
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-scoping/build.sbt
@@ -0,0 +1,44 @@
+lazy val scala213 = "2.13.3"
+lazy val scala212 = "2.12.12"
+lazy val check = taskKey[Unit]("")
+
+lazy val root = (project in file("."))
+  .aggregate(core.projectRefs ++ app.projectRefs: _*)
+  .settings(
+  )
+
+lazy val app = (projectMatrix in file("app"))
+  .aggregate(core, intf)
+  .dependsOn(core % Compile, intf % "compile->compile;test->test")
+  .settings(
+    name := "app"
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213))
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    check := {
+      assert(moduleName.value == "core", s"moduleName is ${moduleName.value}")
+
+      val directs = libraryDependencies.value
+      assert(directs.size == 2, s"$directs")
+    },
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213, scala212))
+  .configure(addStuff)
+
+lazy val intf = (projectMatrix in file("intf"))
+  .settings(
+    check := {
+      assert(moduleName.value == "intf", s"moduleName is ${moduleName.value}")
+    },
+  )
+  .jvmPlatform(autoScalaLibrary = false)
+
+lazy val core213 = core.jvm(scala213)
+
+def addStuff(p: Project): Project = {
+  p.settings(
+    libraryDependencies += "junit" % "junit" % "4.12" % Test
+  )
+}
diff --git a/src/sbt-test/projectMatrix/jvm-with-scoping/core/src/main/scala/Core.scala b/src/sbt-test/projectMatrix/jvm-with-scoping/core/src/main/scala/Core.scala
new file mode 100644
index 000000000..274e01225
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-scoping/core/src/main/scala/Core.scala
@@ -0,0 +1,6 @@
+package a
+
+class Core {
+}
+
+object Core extends Core
diff --git a/src/sbt-test/projectMatrix/jvm-with-scoping/project/plugins.sbt b/src/sbt-test/projectMatrix/jvm-with-scoping/project/plugins.sbt
new file mode 100644
index 000000000..4e80bbafc
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-scoping/project/plugins.sbt
@@ -0,0 +1,5 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
diff --git a/src/sbt-test/projectMatrix/jvm-with-scoping/test b/src/sbt-test/projectMatrix/jvm-with-scoping/test
new file mode 100644
index 000000000..4a2cee2d6
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm-with-scoping/test
@@ -0,0 +1,6 @@
+> compile
+
+$ exists core/target/jvm-2.13/classes/a/Core.class
+$ exists core/target/jvm-2.12/classes/a/Core.class
+
+> core/check
diff --git a/src/sbt-test/projectMatrix/jvm/build.sbt b/src/sbt-test/projectMatrix/jvm/build.sbt
new file mode 100644
index 000000000..65b08b9e6
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm/build.sbt
@@ -0,0 +1,36 @@
+lazy val scala213 = "2.13.3"
+lazy val scala212 = "2.12.12"
+lazy val check = taskKey[Unit]("")
+
+lazy val root = (project in file("."))
+  .aggregate(core.projectRefs ++ app.projectRefs: _*)
+  .settings(
+  )
+
+lazy val app = (projectMatrix in file("app"))
+  .aggregate(core, intf)
+  .dependsOn(core, intf)
+  .settings(
+    name := "app"
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213))
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    check := {
+      assert(moduleName.value == "core", s"moduleName is ${moduleName.value}")
+      assert(projectMatrixBaseDirectory.value == file("core"))
+    },
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213, scala212))
+
+lazy val intf = (projectMatrix in file("intf"))
+  .settings(
+    check := {
+      assert(moduleName.value == "intf", s"moduleName is ${moduleName.value}")
+      assert(projectMatrixBaseDirectory.value == file("intf"))
+    },
+  )
+  .jvmPlatform(autoScalaLibrary = false)
+
+lazy val core213 = core.jvm(scala213)
diff --git a/src/sbt-test/projectMatrix/jvm/core/src/main/scala/Core.scala b/src/sbt-test/projectMatrix/jvm/core/src/main/scala/Core.scala
new file mode 100644
index 000000000..274e01225
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm/core/src/main/scala/Core.scala
@@ -0,0 +1,6 @@
+package a
+
+class Core {
+}
+
+object Core extends Core
diff --git a/src/sbt-test/projectMatrix/jvm/project/plugins.sbt b/src/sbt-test/projectMatrix/jvm/project/plugins.sbt
new file mode 100644
index 000000000..4e80bbafc
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm/project/plugins.sbt
@@ -0,0 +1,5 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
diff --git a/src/sbt-test/projectMatrix/jvm/test b/src/sbt-test/projectMatrix/jvm/test
new file mode 100644
index 000000000..4a2cee2d6
--- /dev/null
+++ b/src/sbt-test/projectMatrix/jvm/test
@@ -0,0 +1,6 @@
+> compile
+
+$ exists core/target/jvm-2.13/classes/a/Core.class
+$ exists core/target/jvm-2.12/classes/a/Core.class
+
+> core/check
diff --git a/src/sbt-test/projectMatrix/lib/build.sbt b/src/sbt-test/projectMatrix/lib/build.sbt
new file mode 100644
index 000000000..4ee7b633d
--- /dev/null
+++ b/src/sbt-test/projectMatrix/lib/build.sbt
@@ -0,0 +1,15 @@
+ThisBuild / version := "0.1.0-SNAPSHOT"
+
+lazy val util = projectMatrix
+  .jvmPlatform(scalaVersions = Seq("2.12.19", "2.13.13"))
+
+lazy val root = (projectMatrix in file("."))
+  .dependsOn(util)
+  .jvmPlatform(scalaVersions = Seq("2.12.19"))
+
+// ss is second system
+lazy val ss = projectMatrix
+  .dependsOn(util)
+  .jvmPlatform(scalaVersions = Seq("2.13.13"))
+
+lazy val strayJar = project
diff --git a/src/sbt-test/projectMatrix/lib/project/plugins.sbt b/src/sbt-test/projectMatrix/lib/project/plugins.sbt
new file mode 100644
index 000000000..4e80bbafc
--- /dev/null
+++ b/src/sbt-test/projectMatrix/lib/project/plugins.sbt
@@ -0,0 +1,5 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
diff --git a/src/sbt-test/projectMatrix/lib/src/main/scala/Main.scala b/src/sbt-test/projectMatrix/lib/src/main/scala/Main.scala
new file mode 100644
index 000000000..ff1427531
--- /dev/null
+++ b/src/sbt-test/projectMatrix/lib/src/main/scala/Main.scala
@@ -0,0 +1,3 @@
+object Main extends App {
+  println(com.example.Lib.getMessage)
+}
diff --git a/src/sbt-test/projectMatrix/lib/ss/src/main/scala/Main.scala b/src/sbt-test/projectMatrix/lib/ss/src/main/scala/Main.scala
new file mode 100644
index 000000000..ff1427531
--- /dev/null
+++ b/src/sbt-test/projectMatrix/lib/ss/src/main/scala/Main.scala
@@ -0,0 +1,3 @@
+object Main extends App {
+  println(com.example.Lib.getMessage)
+}
diff --git a/src/sbt-test/projectMatrix/lib/strayJar/src/main/java/com/example/Lib.java b/src/sbt-test/projectMatrix/lib/strayJar/src/main/java/com/example/Lib.java
new file mode 100644
index 000000000..3740996fa
--- /dev/null
+++ b/src/sbt-test/projectMatrix/lib/strayJar/src/main/java/com/example/Lib.java
@@ -0,0 +1,7 @@
+package com.example;
+
+public class Lib {
+    public static String getMessage() {
+        return "Hello, World!";
+    }
+}
diff --git a/src/sbt-test/projectMatrix/lib/test b/src/sbt-test/projectMatrix/lib/test
new file mode 100644
index 000000000..b55879894
--- /dev/null
+++ b/src/sbt-test/projectMatrix/lib/test
@@ -0,0 +1,15 @@
+# debug
+#> unmanagedBase
+
+# make jar
+> strayJar/package
+
+# check root
+$ mkdir lib
+$ copy-file strayJar/target/scala-2.12/strayjar_2.12-0.1.0-SNAPSHOT.jar lib/strayJar.jar
+> root2_12/compile
+
+# check ss
+$ mkdir ss/lib
+$ copy-file strayJar/target/scala-2.12/strayjar_2.12-0.1.0-SNAPSHOT.jar ss/lib/strayJar.jar
+> ss/compile
diff --git a/src/sbt-test/projectMatrix/native/app/src/main/scala/App.scala b/src/sbt-test/projectMatrix/native/app/src/main/scala/App.scala
new file mode 100644
index 000000000..2cbcd3db7
--- /dev/null
+++ b/src/sbt-test/projectMatrix/native/app/src/main/scala/App.scala
@@ -0,0 +1,8 @@
+package a
+
+object App {
+  def main(args: Array[String]): Unit = {
+    val a = new Core
+    println(s"Hello, world! ${a}")
+  }
+}
diff --git a/src/sbt-test/projectMatrix/native/build.sbt b/src/sbt-test/projectMatrix/native/build.sbt
new file mode 100644
index 000000000..b9a3aab87
--- /dev/null
+++ b/src/sbt-test/projectMatrix/native/build.sbt
@@ -0,0 +1,19 @@
+// lazy val root = (project in file("."))
+//   .aggregate(core.projectRefs ++ app.projectRefs: _*)
+//   .settings(
+//   )
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    name := "core",
+    mainClass in (Compile, run) := Some("a.CoreMain")
+  )
+  .nativePlatform(scalaVersions = Seq("2.11.12"))
+
+lazy val app = (projectMatrix in file("app"))
+  .dependsOn(core)
+  .settings(
+    name := "app",
+    mainClass in (Compile, run) := Some("a.App")
+  )
+  .nativePlatform(scalaVersions = Seq("2.11.12"))
diff --git a/src/sbt-test/projectMatrix/native/core/src/main/scala/Core.scala b/src/sbt-test/projectMatrix/native/core/src/main/scala/Core.scala
new file mode 100644
index 000000000..274e01225
--- /dev/null
+++ b/src/sbt-test/projectMatrix/native/core/src/main/scala/Core.scala
@@ -0,0 +1,6 @@
+package a
+
+class Core {
+}
+
+object Core extends Core
diff --git a/src/sbt-test/projectMatrix/native/core/src/main/scala/CoreMain.scala b/src/sbt-test/projectMatrix/native/core/src/main/scala/CoreMain.scala
new file mode 100644
index 000000000..718013861
--- /dev/null
+++ b/src/sbt-test/projectMatrix/native/core/src/main/scala/CoreMain.scala
@@ -0,0 +1,6 @@
+package a
+
+object CoreMain {
+  def main(args: Array[String]): Unit = {
+  }
+}
diff --git a/src/sbt-test/projectMatrix/native/project/build.properties b/src/sbt-test/projectMatrix/native/project/build.properties
new file mode 100644
index 000000000..dc8f331cc
--- /dev/null
+++ b/src/sbt-test/projectMatrix/native/project/build.properties
@@ -0,0 +1 @@
+sbt.version = 1.4.3
diff --git a/src/sbt-test/projectMatrix/native/project/plugins.sbt b/src/sbt-test/projectMatrix/native/project/plugins.sbt
new file mode 100644
index 000000000..cb79d7dae
--- /dev/null
+++ b/src/sbt-test/projectMatrix/native/project/plugins.sbt
@@ -0,0 +1,6 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
+addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.4.0")
diff --git a/src/sbt-test/projectMatrix/native/test b/src/sbt-test/projectMatrix/native/test
new file mode 100644
index 000000000..d4d53c054
--- /dev/null
+++ b/src/sbt-test/projectMatrix/native/test
@@ -0,0 +1,4 @@
+> nativeLink
+
+$ exists app/target/native-2.11/app-out
+$ exists core/target/native-2.11/core-out
diff --git a/src/sbt-test/projectMatrix/projectAxes/build.sbt b/src/sbt-test/projectMatrix/projectAxes/build.sbt
new file mode 100644
index 000000000..87667c258
--- /dev/null
+++ b/src/sbt-test/projectMatrix/projectAxes/build.sbt
@@ -0,0 +1,56 @@
+lazy val scala213 = "2.13.3"
+lazy val scala212 = "2.12.12"
+lazy val check = taskKey[Unit]("")
+lazy val platformTest = settingKey[String]("")
+lazy val configTest = settingKey[String]("")
+
+
+lazy val config12 = ConfigAxis("Config1_2", "config1.2")
+lazy val config13 = ConfigAxis("Config1_3", "config1.3")
+
+lazy val root = (project in file("."))
+  .aggregate((core.projectRefs ++ custom.projectRefs):_*)
+
+lazy val core = (projectMatrix in file("core"))
+  .settings(
+    check := {
+       assert(platformTest.value.endsWith("-platform"))
+       assert(projectMatrixBaseDirectory.value == file("core"))
+    },
+  )
+  .jvmPlatform(scalaVersions = Seq(scala213, scala212))
+  .jsPlatform(scalaVersions = Seq(scala212))
+  .settings(platformSettings)
+
+lazy val custom =
+  (projectMatrix in file("custom"))
+  .customRow(
+    scalaVersions = Seq(scala212),
+    axisValues = Seq(config13, VirtualAxis.jvm),
+    _.settings()
+  )
+  .settings(platformSettings)
+  .settings(customSettings)
+  .settings(
+    check := {
+      assert(platformTest.value.endsWith("-platform"))
+      assert(configTest.value.startsWith("config for"))
+    }
+  )
+
+
+lazy val platformSettings = Seq[Def.Setting[_]](
+    platformTest := {
+      if(virtualAxes.value.contains(sbt.VirtualAxis.js)) "js-platform"
+      else if(virtualAxes.value.contains(sbt.VirtualAxis.jvm)) "jvm-platform"
+      else throw new RuntimeException(s"Something must be wrong (built-in platforms test) - virtualAxes value is ${virtualAxes.value}")
+    }
+)
+
+lazy val customSettings = Seq[Def.Setting[_]](
+  configTest := {
+    if(virtualAxes.value.contains(config12)) "config for 1.2"
+    else if (virtualAxes.value.contains(config13)) "config for 1.3"
+    else throw new RuntimeException(s"Something must be wrong (custom axis test ) - virtualAxes value is ${virtualAxes.value}")
+  }
+)
diff --git a/src/sbt-test/projectMatrix/projectAxes/project/ConfigAxis.scala b/src/sbt-test/projectMatrix/projectAxes/project/ConfigAxis.scala
new file mode 100644
index 000000000..bdabcb757
--- /dev/null
+++ b/src/sbt-test/projectMatrix/projectAxes/project/ConfigAxis.scala
@@ -0,0 +1,3 @@
+import sbt._
+
+case class ConfigAxis(idSuffix: String, directorySuffix: String) extends VirtualAxis.WeakAxis
diff --git a/src/sbt-test/projectMatrix/projectAxes/project/plugins.sbt b/src/sbt-test/projectMatrix/projectAxes/project/plugins.sbt
new file mode 100644
index 000000000..60a69f1df
--- /dev/null
+++ b/src/sbt-test/projectMatrix/projectAxes/project/plugins.sbt
@@ -0,0 +1,7 @@
+sys.props.get("plugin.version") match {
+  case Some(x) => addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % x)
+  case _ => sys.error("""|The system property 'plugin.version' is not defined.
+                         |Specify this property using the scriptedLaunchOpts -D.""".stripMargin)
+}
+
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.3.0")
diff --git a/src/sbt-test/projectMatrix/projectAxes/test b/src/sbt-test/projectMatrix/projectAxes/test
new file mode 100644
index 000000000..e3bd83da1
--- /dev/null
+++ b/src/sbt-test/projectMatrix/projectAxes/test
@@ -0,0 +1,2 @@
+> compile
+> check