i3-sensible-editor man page
i3-sensible-editor — launches $EDITOR with fallbacks
i3-sensible-editor is used by i3-nagbar(1) when you click on the edit button.
It tries to start one of the following (in that order):
Please don’t complain about the order: If the user has any preference, they will have $VISUAL or $EDITOR set.
Michael Stapelberg and contributors