I'm having a Linux brainfart moment.

My Fedora and Devuan systems cache old installs for rollback. Fedora presents these in the boot selection. I can't find this in Debian, it isn't in the package manager and the searches I've tried haven't been helpful. Where is this in Debian? What keyword should I be searching for?

@noodle this is the point where Debian totally sucks. My condolences.

You had to install a specific version and pin it somehow (I don't know how, never did that).

Or use backups. They rescued me many times.