Yes so in order to make parent-based filtering work in theory is to have some "project" kind that is separate from repo kind.

But if we did that, it would be equivalent to having issues and tasks separated.

The benefit I see on the side of having both projects and repos though, is that one project could encompass multiple repos and we don't yet have that afaik.

That would make it useful enough to assign a separate kind and all the non-repo tasks could refer to that instead of the repo as a parent.