Demonstration for https://stackoverflow.com/questions/18736435/git-query-regarding-merging-notes-ref

cd /tmp
dir=$(mktemp -d)
cd $dir
git init
git commit --allow-empty -mInit
git commit --allow-empty -ma
git commit --allow-empty -mb
git commit --allow-empty -mc
cd ..
dir_remote=$(mktemp -d)
cd $dir_remote
git init
git config receive.denyCurrentBranch ignore
cd $dir
git remote add origin $dir_remote
git push origin main
# Two notes in the “local” repo
git notes add -mc
git notes add -mb @~
# And one note in the “remote” repo
cd $dir_remote
git notes add -ma @~~
cd $dir
git fetch origin refs/notes/commits:refs/notes/origin/commits
# Backup before merge
git tag before-merge refs/notes/commits
git notes merge -v origin/commits
# Undo merge
git update-ref refs/notes/commits before-merge
# Do rebase instead
git switch --detach notes/commits
git rebase notes/origin/commits
git update-ref refs/notes/commits @
git switch -q -
git tag --delete before-merge