The last commit on the GitLab mirror is cf485148bd9f4d4520d13e2169997cd72464f3c0. On GitHub, it's not the last one, but it's on the first page (not that much commits since).
Because it's the same SHA, and because of the way git works, we know that all the history before it is exactly the same on GitHub and GitLab.
Because it's the same SHA, and because of the way git works, we know that all the history before it is exactly the same on GitHub and GitLab.