4 * git revert, stash, rebase
13 - prune, fsck, pack-refs, gc, count-objects, unpack-objects
15 * email/patch integration
16 - request-pull(email_address), git-am, git-apply
19 * compatible with git 1.4
23 * More Git::Status methods
26 * Speed up through pure ruby
28 * Speed up through C bindings to libgit-thin