Have you tested this when there are _lots_ of changes in a repository? Sometimes it's necessary for people to add for instance a whole new library to their project with perhaps hundreds of files. Ungit kiind of handles this right now (though it could get better) but I'd prefer to not make it worse neither.

But I haven't tested this myself so if it performs equally well for lots of files I'm fine with it. If not we should start looking at alternative solutions such as looking at the ending of the file instead (which would be totally fine for me)