It's not hard (not claiming it's sensible, but still). Do gitk --all, walk back to the tag, right click and create a new branch. This is even possible if there

It's not hard (not claiming it's sensible, but still). Do gitk --all, walk back to the tag, right click and create a new branch. This is even possible if there was no tag (just a recognizable revision), or if you want to create a tag retroactively.