We have a https://git.cloudron.io/playground/ for such repos. TBF, it doesn't matter where your repo is hosted . Your link is equally sharable but you can also use ours if you think yours is more transient.
@necrevistonnezr uhhhmmm
Since I set up everything with ansible, I once found this out, put in my playbook and forgot about it.
That it does not exist in the deb doc is questionable.
Thanks to everyone for the responses. I fully understand the backups now and have reported to my board that it's indeed production ready for our organization.
I cloned my grav theme repository (https link) into app/code/user/themes and use it in one direction only by pulling changes with sudo -u www-data git pull to update the website.
The git-sync extension basically adds (automatic) pushing as well by initializing a git directory in the app/code/user directory.