Question: I want to do the release notes by using git notes, but I am not sure if other people change my git notes by using the same ref. 

BTW, `chmod 444 .git/refs/notes/abc_test` & `.git/logs/refs/notes/abc_test` does not work.

Answer: 
I don't think you really can protect published git notes.

What you can do is put them in an explicit [namespace](https://stackoverflow.com/a/5213110/6309), as mentioned [in here](http://lists-archives.com/git/714256-git-notes-usage.html):

> 
> I think for "typical usage" one stores others' notes in a different place anyways, e.g. I store Thomas' list-notes in refs/remotes/trast/notes/ so that they don't interfer with my own notes.
> 
> 
> 

If in the same namespace, then [they can be merged](http://vmiklos.hu/blog/git-notes-merge.html):

```
git checkout refs/notes/commits
git fetch origin refs/notes/commits
git merge FETCH_HEAD
git update-ref refs/notes/commits HEAD
git checkout master

```

But that would change their content.
This [Git man page](https://help.github.com/articles/remove-sensitive-data) details how to remove sensitive data and it states that you can

> 
> add [the file] to the .gitignore to ensure it is not accidentally re-committed
> 
> 
> 

I do not think that it is possible to have a file versioned, but not visible to others, due to the distributed model Git uses. Setting the file to read only will not have the desired effect once the file is copied to another user's repository.

Does that answer your question?