I recently had a pull request approved. I deleted the feature branch afterwards, as it was not needed anymore, and I also deleted the fork, because I didn't need it anymore either. Now the pull request came from an "unknown repository":

I understand that the reason is that the repo's name is retrieved dynamically and that it doesn't exist anymore when it's deleted, but this behavior is pretty jarring and I have to wonder if it's intended. I'd rather not keep old, out-of-date forks around just so past pull requests aren't "broken".

I guess there might be a privacy concern here, as deleted/private repos should probably not be publicized in any way, but seeing as the old fork's name is saved for posterity in the merge commit message, that shouldn't really be a problem.