This happens sometimes when private repos change hands. I've worked at places where we've been given zips of git repos – commit messages reference PR and issue

This happens sometimes when private repos change hands. I've worked at places where we've been given zips of git repos – commit messages reference PR and issue #'s from long distant organizations. I've since started policing PRs whose commit messages reference things inside of our GitHub. At least provide a summary of what you're linking, for the worst case future.