Can some kind soul help me out please?

I want to backup my abbrev_defs file exactly the same as everything else is backed up, i.e. when there is a change to it, a backup is triggered to save it in ~/.emacs.d/backups. Although the position is slightly complicated as its not normally open in any buffer, so the backup would presumably have to be triggered on the source files changing.

I've googled but haven't found any instances of it being backed up, so there isn't anything seemingly available for me to hack from or with. So can some kind soul help with some working code, or guidance to a non-programmer to achieve this please?

Thanks
Sharon.
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