Geno observed that our code in PageEditingHandler::onRecentChange_save and our code in ZObjectAuthorization::getRequiredEditRights are doing closely-related work, both using the output of a ZObjectDiffer, but are different, and could potentially be combined.

OTOH, the fundamentals of what they're doing ("what's the right needed for each change here?" vs. "what's the simplest label that can describe this change?") are a bit different, so it might be hard to reconcile.