We had avoided using systemd-run's --working-directory flag because it was added in systemd v229 or similar, but now we can assume we have that.
I saw an opportunity to help me, my future self, and hopefully others to understand the code better by refactoring it a bit and adding some comments with references to systemd stuff, so I took it.
--working-directory
flag because it was added in systemd v229 or similar, but now we can assume we have that.