# refs/ffqrebase-prev/BRANCH BRANCH may be refs/...; if not it means
# refs/ffqrebase-base/BRANCH refs/heads/BRANCH
# zero, one, or both of these may exist
# refs/ffqrebase-prev/BRANCH BRANCH may be refs/...; if not it means
# refs/ffqrebase-base/BRANCH refs/heads/BRANCH
# zero, one, or both of these may exist