Would it make sense to also add/sync an .editorconfig file (https://editorconfig.org/)? Only the play-mailer has it right now: https://github.com/playframework/play-mailer/blob/main/.editorconfig
IntelliJ support scalafmt out of the box, however maybe it makes sense for other IDEs and editors to define some rules? (Also possible for non Scala/non Java files).
Not sure, just a thought since I saw that file in play-mailer.

Would it make sense to also add/sync an .editorconfig file (https://editorconfig.org/)?

I think yes. I think we should unify contribution rules as max as possible for simplify work contributors and maintainers when they is switching between many Play repositories.

Time for a sync job 😉