I'm wondering what the "because when we read it in, we mangle it" part really means... does this mean that there's no way to reference the commit (signaling that it's just a reference and has no actual data) without actually reading the contents of it?

-- Update: just realized why it wouldn't make sense: `git push` would send only the delta from the previous commit and the previous commit is... non-existent (we only know it's ID), so we'd be back in square 1 (sending everything).