TIL: #Git has its own version of $EDITOR - $GIT_EDITOR - that it looks up with a higher priority, which means it is possible to optionally set a different editor for your Git commit messages/rebase to-do's than everything else.
One specific place where it's useful is integrated terminals inside IDEs, which often allow you to inject additional environment variables and thus you can set $GIT_EDITOR there to edit commit messages from the IDE while using the Git CLI
https://git-scm.com/docs/git-var#Documentation/git-var.txt-GITEDITOR