diff --git a/main/Build.scala b/main/Build.scala
index 191364178..5374eebf6 100644
--- a/main/Build.scala
+++ b/main/Build.scala
@@ -192,9 +192,11 @@ object BuildStreams
 		val scope = scoped.scope
 		pathComponent(scope.config, scoped, "config")(_.name) ::
 		pathComponent(scope.task, scoped, "task")(_.label) ::
-		pathComponent(scope.extra, scoped, "extra")(_ => error("Unimplemented")) ::
+		pathComponent(scope.extra, scoped, "extra")(showAMap) ::
 		Nil
 	}
+	def showAMap(a: AttributeMap): String =
+		a.entries.toSeq.sortBy(_.key.label).map { case AttributeEntry(key, value) => key.label + "=" + value.toString } mkString(" ")
 	def projectPath(units: Map[URI, LoadedBuildUnit], root: URI, scoped: ScopedKey[_], data: Settings[Scope]): File =
 		scoped.scope.project match
 		{
diff --git a/util/collection/Attributes.scala b/util/collection/Attributes.scala
index 4c3a16873..f275cdbe0 100644
--- a/util/collection/Attributes.scala
+++ b/util/collection/Attributes.scala
@@ -72,9 +72,9 @@ private class BasicAttributeMap(private val backing: Map[AttributeKey[_], Any])
 }
 
 // type inference required less generality
-final case class AttributeEntry[T](a: AttributeKey[T], b: T)
+final case class AttributeEntry[T](key: AttributeKey[T], value: T)
 {
-	override def toString = a.label + ": " + b
+	override def toString = key.label + ": " + value
 }
 
 final case class Attributed[D](data: D)(val metadata: AttributeMap)