> I’ve been using autofixup for this and it’s been ok but not great, it can be quite slow as things grown, and it doesn’t say anything when there was no match so it’s easy to miss. How does absorb surface that?

I haven't used autofixup, but:

* git-absorb has always been pretty snappy. I don't think it scales with repository size.

* If there's no match, then the things that don't match stay in the staging area and don't make it into a commit. git-absorb will also note this in its output after running it.