The COLLABORATOR_GUIDE doesn't seem to cover how to revert commits, and specifically what the commit message should be. I think we should try to agree what the standard process is.

For single commits with git revert HASH:

1. Leave the commit message as is.
2. Modify (not least to pass node-validate-commit), e.g. fs: Revert throw on invalid callbacks #12976

For multiple commits with git revert FROM...TO:

1. Leave as individual commits
2. Format commit messages, e.g. Revert commits that cause failing tests on Windows CI #4679
3. Squash the commits