OK I really tried but my Googlefu seems lacking. Any pointer, pretty please?

Oh it was mostly a pun blending prolog like backtracking at the os-process level.

I figured. I went down the rabbit hole, prolo, and prolog and hoped it wasn't a pun :-) yes I think backtracking as a general OS mechanism. Since the kernel already knows which pages differ between both processes, and could 'just' plug back any socket, file, shm, pipe 'as is' when 'restoring'. All the state is know to the OS!

Maybe something with ebpf in twelve years...

and live exploratory debugging when your fs fails

Well if I could synchronise that with lvm snapshots and go back... Once you start going the backtracking rabbit hole, there's lots of thing one can imagine.

time to make a pull-request

Wish I had the chops. Time to find money to have someone do it you mean.

who sets up the kickstarter ? :p