You asked for a file, but I would use git to save a set of changes - it's much easier to track than a file.
Create a new branch
git checkout -b saved_stash
the prefix pops up, adds and fixes
git stash pop git add . git commit -m 'save stash for later'
If you want to use it again, check the branch, reset commit and add to it again
git checkout saved_stash git reset
At this point, you should have the same state that you saved.
(typed in a team, teams can be slightly disabled - I hope only a little)
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