Yes, I'm talking about coordinating PRs against multiple repos. Obviously, this isn't a git feature, this is something that Github would need to do, just like issues/webhooks/comments are not git features.

This is one of the reasons cited for monorepos, you can make a single atomic commit/PR that changes some API, and the consumers of that API.

As it is now, you end up writing a warning comment to merge some other PR at the same time and hoping your reviewers read it.