For launching the new scala command (SIP 46), we want to cache the compiler artefacts in a local repo that is bundled in the zip, so Scala CLI can resolve the artefacts from here. This isn't possible to do within sbt from the librarymanagement API because there is no configuration to allow caching of local artefacts.
what happens is coursier will resolve all library dependencies and put them in the cache, but anything in local repo is skipped. There's a setting localArtifactsShouldBeCached which should prevent skipping, but it is only configurable from Coursier CLI.
refs: see scala/scala3#20098