diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 8afe51adf..b9d132b8e 100644
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -985,15 +985,6 @@ object Defaults extends BuildCommon {
           ) ++ old
         else old
       },
-      scalacOptions := {
-        val old = scalacOptions.value
-        if (
-          sbtPlugin.value && VersionNumber(scalaVersion.value)
-            .matchesSemVer(SemanticSelector("=2.12 >=2.12.13"))
-        )
-          old ++ Seq("-Wconf:cat=unused-nowarn:s", "-Xsource:3")
-        else old
-      },
       persistJarClasspath :== true,
       classpathEntryDefinesClassVF := {
         val cache =