I call this nonsense host ‘Ghost’, for me it’s similar to a tape backup solution. Fairly simple concept, it’s an old Pi1 + external mechanical drive that sits dormant with its ethernet off. Once a month, at a random time and random date it enables the ethernet, spins up the drive and pulls data from the main server to update its drive then goes black until next month. The only way to check or maintain the pi is a push button that toggles the ethernet interface. I slapped it together with some scrap wood, spare hardware and screwed it to a 2x4 in a dark corner of my basement. It’s my 5th string backup, the ultimate insurance policy because I’m mental.
I very much feel the desire to stay away from Git repos for singular scripts like this. Maybe consider making it a gist though. Easier to keep track of by starring it in GitHub and perhaps even iterate on it in the future. :)
I use Joplin notes to track my code revisions. It’s incredibly crude but it works and keeps my documention private and is also my wiki for each server so I know what the heck I setup and did.