Started off like JENKINS-50696, and…

SCM provider is not available for scm:null:https://github.com/jglick/mrp-test

Um, what? OK, importing existing Maven projects from disk seems to work better. Went to try to configure Maven 3.5.3, and then the IDE froze up and had to be killed and restarted.

Anyway, finally got the downstream project opened also, and TwoTest to run both against a MRP release and against a snapshot and against an Incrementals release and so on.