> how do we actually know that that pull request has gone through all the checks
gerrit flags all reviews and checks into git notes, which can be downloaded and displayed with a little bit of configuration: https://tylercipriani.com/blog/2022/11/19/git-notes-gits-coo...
This doesn't prevent an admin from cheating and editing the notes manually, but it's a good audit trail if you trust the "forge".