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 Maybe you mean filesystem snapshots? (I haven't used it myself, but I know the functionality exists.)
I found a package called "snapper" which seems to facilitate this.