I might be missing something but isn't .project already covered by project-vc-extra-root-markers. I can't really see what else this local project type provides that that wouldn't.
This is missing functionality. I see no issue adding something like this to projection, although personally I'm not really a big fan of state restoration features in editors (they always miss some subtlety in the setup). I'll add this as a good feature contribution, happy to accept PRs.
I read about this and it looks like this might work.
I will try to come up with a PR, but it might not be anytime soon. I guess you are not in a hurry for this feature so it won't be a problem if I take time.
@karthink has written project-x which provides at least two useful features:
.project
file.This is a perfect candidate for inclusion in your package; we will have a single lightweight project management solution.