Only check changed hunks
Some workflows would like to be able to only send feedback to contributors about the changes they're making as opposed to preexisting unrecognized content.
It should be fairly easy to use the equivalent of
git blame BASE..HEAD -- file to identify which line numbers should be checked and only check them.
(It's possible the implementation will use porcelain output as opposed to actually using the naive
git blame BASE..HEAD, but that's a minor implementation detail.)