Integration with the share extension needs improvement. Right now we've seen some odd bugs.

Address commentary in manifest.excludedmanifestrevlog.add - specifically we should improve the collaboration with core so that add() never gets called on an excluded directory and we can improve the stand-in to raise a ProgrammingError.

Reason more completely about rename-filtering logic in narrowfilelog. There could be some surprises lurking there.

Formally document the narrowspec format. Unify with sparse, if at all possible. For bonus points, unify with the server-specified narrowspec format.

narrowrepo.setnarrowpats() or narrowspec.save() need to make sure they're holding the wlock.