diff --git a/internal/util-complete/src/main/scala/sbt/internal/util/complete/HistoryCommands.scala b/internal/util-complete/src/main/scala/sbt/internal/util/complete/HistoryCommands.scala
index 818ea077e..e3670ade5 100644
--- a/internal/util-complete/src/main/scala/sbt/internal/util/complete/HistoryCommands.scala
+++ b/internal/util-complete/src/main/scala/sbt/internal/util/complete/HistoryCommands.scala
@@ -10,7 +10,7 @@ package sbt.internal.util
 package complete
 
 import sbt.io.IO
-import Util.{ AnyOps, nil }
+import Util.*
 
 object HistoryCommands {
   val Start = "!"
diff --git a/internal/util-core/src/main/scala/sbt/internal/util/Util.scala b/internal/util-core/src/main/scala/sbt/internal/util/Util.scala
index c938471b6..028cd79a2 100644
--- a/internal/util-core/src/main/scala/sbt/internal/util/Util.scala
+++ b/internal/util-core/src/main/scala/sbt/internal/util/Util.scala
@@ -68,7 +68,7 @@ object Util {
   def nilSeq[A]: Seq[A] = Seq.empty[A]
   def none[A]: Option[A] = (None: Option[A])
 
-  implicit class AnyOps[A](private val value: A) extends AnyVal {
+  extension [A](value: A) {
     def some: Option[A] = (Some(value): Option[A])
   }
 }
diff --git a/internal/util-logging/src/main/scala/sbt/internal/util/Terminal.scala b/internal/util-logging/src/main/scala/sbt/internal/util/Terminal.scala
index ead919534..bcdfed879 100644
--- a/internal/util-logging/src/main/scala/sbt/internal/util/Terminal.scala
+++ b/internal/util-logging/src/main/scala/sbt/internal/util/Terminal.scala
@@ -246,7 +246,7 @@ object Terminal {
   }
 
   private[sbt] def set(terminal: Terminal): Terminal = activeTerminal.getAndSet(terminal)
-  implicit class TerminalOps(private val term: Terminal) extends AnyVal {
+  extension (term: Terminal) {
     def ansi(richString: => String, string: => String): String =
       if (term.isAnsiSupported) richString else string
     /*
diff --git a/internal/util-logging/src/main/scala/sbt/util/ShowLines.scala b/internal/util-logging/src/main/scala/sbt/util/ShowLines.scala
index f6ea6107e..9764e6259 100644
--- a/internal/util-logging/src/main/scala/sbt/util/ShowLines.scala
+++ b/internal/util-logging/src/main/scala/sbt/util/ShowLines.scala
@@ -17,7 +17,7 @@ object ShowLines {
       def showLines(a: A): Seq[String] = f(a)
     }
 
-  implicit class ShowLinesOp[A: ShowLines](a: A) {
+  extension [A: ShowLines](a: A) {
     def lines: Seq[String] = implicitly[ShowLines[A]].showLines(a)
   }
 }
diff --git a/lm-coursier/src/main/scala/lmcoursier/syntax/package.scala b/lm-coursier/src/main/scala/lmcoursier/syntax/package.scala
index 676fc1eae..bec5a6710 100644
--- a/lm-coursier/src/main/scala/lmcoursier/syntax/package.scala
+++ b/lm-coursier/src/main/scala/lmcoursier/syntax/package.scala
@@ -10,7 +10,7 @@ import scala.concurrent.duration.{ Duration, FiniteDuration }
 import java.io.File
 
 package object syntax {
-  implicit class CoursierConfigurationModule(value: CoursierConfiguration.type) {
+  extension (value: CoursierConfiguration.type) {
     @deprecated(
       "Legacy cache location support was dropped, this method does nothing.",
       "2.0.0-RC6-10"
@@ -80,7 +80,7 @@ package object syntax {
       )
   }
 
-  implicit class CoursierConfigurationOp(value: CoursierConfiguration) {
+  extension (value: CoursierConfiguration) {
     def withLog(log: Logger): CoursierConfiguration =
       value.withLog(Option(log))
     def withSbtScalaOrganization(sbtScalaOrganization: String): CoursierConfiguration =
@@ -122,7 +122,7 @@ package object syntax {
       value.withRetry(Some((retry._1, retry._2)))
   }
 
-  implicit class PublicationOp(value: Publication) {
+  extension (value: Publication) {
     def attributes: Attributes =
       Attributes(value.`type`, value.classifier)
 
@@ -132,7 +132,7 @@ package object syntax {
         .withClassifier(attributes.classifier)
   }
 
-  implicit class DependencyModule(value: Dependency.type) {
+  extension (value: Dependency.type) {
     def apply(
         module: Module,
         version: String,
@@ -153,7 +153,7 @@ package object syntax {
       )
   }
 
-  implicit class DependencyOp(value: Dependency) {
+  extension (value: Dependency) {
     def attributes: Attributes = value.publication.attributes
 
     def withAttributes(attributes: Attributes): Dependency =
@@ -164,7 +164,7 @@ package object syntax {
       )
   }
 
-  implicit class ModuleMatchersModule(value: ModuleMatchers.type) {
+  extension (value: ModuleMatchers.type) {
     def all: ModuleMatchers =
       ModuleMatchers(Set.empty, Set.empty)
     def only(organization: String, moduleName: String): ModuleMatchers =
@@ -177,19 +177,19 @@ package object syntax {
       ModuleMatchers(Set.empty, Set(mod), includeByDefault = false)
   }
 
-  implicit class StrictOp(value: Strict) {
+  extension (value: Strict) {
     def addInclude(include: (String, String)*): Strict =
       value.withInclude(value.include ++ include)
     def addExclude(exclude: (String, String)*): Strict =
       value.withExclude(value.exclude ++ exclude)
   }
 
-  implicit class AuthenticationModule(value: Authentication.type) {
+  extension (value: Authentication.type) {
     def apply(headers: Seq[(String, String)]): Authentication =
       Authentication("", "").withHeaders(headers)
   }
 
-  implicit class DirectCredentialsModule(value: DirectCredentials.type) {
+  extension (value: DirectCredentials.type) {
     def apply(host: String, username: String, password: String, realm: String): DirectCredentials =
       DirectCredentials(host, username, password, Option(realm))
     def apply(
@@ -202,12 +202,12 @@ package object syntax {
       DirectCredentials(host, username, password, Option(realm))
   }
 
-  implicit class DirectCredentialsOp(value: DirectCredentials) {
+  extension (value: DirectCredentials) {
     def withRealm(realm: String): DirectCredentials =
       value.withRealm(Option(realm))
   }
 
-  implicit class CredentialsModule(value: Credentials.type) {
+  extension (value: Credentials.type) {
     def apply(): DirectCredentials = DirectCredentials()
     def apply(host: String, username: String, password: String): DirectCredentials =
       DirectCredentials(host, username, password)
diff --git a/main-actions/src/main/scala/sbt/Console.scala b/main-actions/src/main/scala/sbt/Console.scala
index a0a07289e..5c0856c53 100644
--- a/main-actions/src/main/scala/sbt/Console.scala
+++ b/main-actions/src/main/scala/sbt/Console.scala
@@ -12,7 +12,7 @@ import java.io.File
 import java.nio.channels.ClosedChannelException
 import sbt.internal.inc.{ AnalyzingCompiler, MappedFileConverter, PlainVirtualFile }
 import sbt.internal.util.{ DeprecatedJLine, Terminal }
-import sbt.internal.util.Terminal.TerminalOps
+import sbt.internal.util.Terminal.*
 import sbt.util.Logger
 import xsbti.compile.{ Compilers, Inputs }
 
diff --git a/main-actions/src/main/scala/sbt/ForkTests.scala b/main-actions/src/main/scala/sbt/ForkTests.scala
index b13711a34..ca804ee9f 100755
--- a/main-actions/src/main/scala/sbt/ForkTests.scala
+++ b/main-actions/src/main/scala/sbt/ForkTests.scala
@@ -18,7 +18,7 @@ import sbt.io.IO
 import sbt.util.Logger
 import sbt.ConcurrentRestrictions.Tag
 import sbt.protocol.testing._
-import sbt.internal.util.Util.{ AnyOps, none }
+import sbt.internal.util.Util.*
 import sbt.internal.util.{ Terminal => UTerminal }
 import xsbti.{ FileConverter, HashedVirtualFileRef }
 
diff --git a/main-command/src/main/scala/sbt/BasicCommands.scala b/main-command/src/main/scala/sbt/BasicCommands.scala
index 6ec2d0412..39c71e768 100644
--- a/main-command/src/main/scala/sbt/BasicCommands.scala
+++ b/main-command/src/main/scala/sbt/BasicCommands.scala
@@ -22,7 +22,7 @@ import sbt.internal.util.complete.{
   History => CHistory
 }
 import sbt.internal.util.Types.{ const, idFun }
-import sbt.internal.util.Util.{ AnyOps, nil, nilSeq, none }
+import sbt.internal.util.Util.*
 import sbt.internal.inc.classpath.ClasspathUtil.toLoader
 import sbt.internal.inc.ModuleUtilities
 import sbt.internal.client.NetworkClient
diff --git a/main-command/src/main/scala/sbt/internal/LabeledFunctions.scala b/main-command/src/main/scala/sbt/internal/LabeledFunctions.scala
index b5a8949b8..31709ccef 100644
--- a/main-command/src/main/scala/sbt/internal/LabeledFunctions.scala
+++ b/main-command/src/main/scala/sbt/internal/LabeledFunctions.scala
@@ -26,7 +26,7 @@ private[sbt] object LabeledFunctions {
    * @param f the function to extend
    * @tparam R the function result type
    */
-  private[sbt] implicit class Function0Ops[R](val f: () => R) extends AnyVal {
+  extension [R](f: () => R) {
 
     /**
      * Add a label to the function.
@@ -42,7 +42,7 @@ private[sbt] object LabeledFunctions {
    * @tparam T the input parameter
    * @tparam R the function result type
    */
-  private[sbt] implicit class Function1Ops[T, R](val f: T => R) extends AnyVal {
+  extension [T, R](f: T => R) {
 
     /**
      * Add a label to the function.
@@ -59,7 +59,7 @@ private[sbt] object LabeledFunctions {
    * @tparam T2 the second function input parameter
    * @tparam R the function result type
    */
-  private[sbt] implicit class Function2Ops[T1, T2, R](val f: (T1, T2) => R) extends AnyVal {
+  extension [T1, T2, R](f: (T1, T2) => R) {
 
     /**
      * Add a label to the function.
@@ -77,7 +77,7 @@ private[sbt] object LabeledFunctions {
    * @tparam T3 the third function input parameter
    * @tparam R the function result type
    */
-  private[sbt] implicit class Function3Ops[T1, T2, T3, R](val f: (T1, T2, T3) => R) extends AnyVal {
+  extension [T1, T2, T3, R](f: (T1, T2, T3) => R) {
 
     /**
      * Add a label to the function.
@@ -96,8 +96,7 @@ private[sbt] object LabeledFunctions {
    * @tparam T4 the fourth function input parameter
    * @tparam R the function result type
    */
-  private[sbt] implicit class Function4Ops[T1, T2, T3, T4, R](val f: (T1, T2, T3, T4) => R)
-      extends AnyVal {
+  extension [T1, T2, T3, T4, R](f: (T1, T2, T3, T4) => R) {
 
     /**
      * Add a label to the function.
diff --git a/main-command/src/main/scala/sbt/internal/util/JoinThread.scala b/main-command/src/main/scala/sbt/internal/util/JoinThread.scala
index 0acf23e0e..be162e584 100644
--- a/main-command/src/main/scala/sbt/internal/util/JoinThread.scala
+++ b/main-command/src/main/scala/sbt/internal/util/JoinThread.scala
@@ -13,7 +13,7 @@ import scala.concurrent.duration._
 import java.util.concurrent.TimeoutException
 
 object JoinThread {
-  implicit class ThreadOps(val t: Thread) extends AnyVal {
+  extension (t: Thread) {
     def joinFor(duration: FiniteDuration): Unit = {
       val deadline = duration.fromNow
       @tailrec def impl(): Unit = {
diff --git a/main/src/main/scala/sbt/internal/BuildLoader.scala b/main/src/main/scala/sbt/internal/BuildLoader.scala
index 7fae1e78e..1650d6c16 100644
--- a/main/src/main/scala/sbt/internal/BuildLoader.scala
+++ b/main/src/main/scala/sbt/internal/BuildLoader.scala
@@ -17,11 +17,11 @@ import sbt.util.Logger
 import sbt.librarymanagement.ModuleID
 
 private[internal] object Alternatives {
-  private[internal] implicit class Alternative[A, B](val f: A => Option[B]) {
+  extension [A, B](f: A => Option[B]) {
     def |(g: A => Option[B]): A => Option[B] = (a: A) => f(a) orElse g(a)
   }
 }
-import Alternatives.Alternative
+import Alternatives.*
 final class MultiHandler[S, T](
     builtIn: S => Option[T],
     root: Option[S => Option[T]],
diff --git a/main/src/main/scala/sbt/internal/ClassLoaders.scala b/main/src/main/scala/sbt/internal/ClassLoaders.scala
index 290deee6f..1d7156b0d 100644
--- a/main/src/main/scala/sbt/internal/ClassLoaders.scala
+++ b/main/src/main/scala/sbt/internal/ClassLoaders.scala
@@ -30,7 +30,7 @@ import xsbti.ArtifactInfo
 import xsbti.HashedVirtualFileRef
 
 private[sbt] object ClassLoaders {
-  private implicit class SeqFileOps(val files: Seq[File]) extends AnyVal {
+  extension (files: Seq[File]) {
     def urls: Array[URL] = files.toArray.map(_.toURI.toURL)
   }
   private val interfaceLoader = classOf[sbt.testing.Framework].getClassLoader
diff --git a/run/src/main/scala/sbt/Fork.scala b/run/src/main/scala/sbt/Fork.scala
index abf6effa3..4f240ab48 100644
--- a/run/src/main/scala/sbt/Fork.scala
+++ b/run/src/main/scala/sbt/Fork.scala
@@ -14,7 +14,7 @@ import java.lang.ProcessBuilder.Redirect
 import scala.sys.process.Process
 import OutputStrategy._
 import sbt.internal.util.{ RunningProcesses, Util }
-import Util.{ AnyOps, none }
+import Util.*
 
 import java.lang.{ ProcessBuilder => JProcessBuilder }
 import java.util.Locale
diff --git a/run/src/main/scala/sbt/SelectMainClass.scala b/run/src/main/scala/sbt/SelectMainClass.scala
index 3ec208b8f..c4865f6c7 100644
--- a/run/src/main/scala/sbt/SelectMainClass.scala
+++ b/run/src/main/scala/sbt/SelectMainClass.scala
@@ -9,7 +9,7 @@
 package sbt
 
 import sbt.internal.util.ConsoleAppender.ClearScreenAfterCursor
-import sbt.internal.util.Util.{ AnyOps, none }
+import sbt.internal.util.Util.*
 import scala.annotation.tailrec
 
 object SelectMainClass {