The old commits with old comments are still there for a while and 'git reset --hard' can be used to get back to the old way. After a rebase there is a ref named

The old commits with old comments are still there for a while and 'git reset --hard' can be used to get back to the old way. After a rebase there is a ref named ORIG_HEAD and a log in .git/logs/refs/heads (though I didn't really know that, I just went looking through my .git folder). If you do a big force push on a remote repository you could keep the old stuff in a tag or a branch.