The diff functionality for items should be exposed through the MW API. This way changes to an item can be turned into a patch. I.e. if someone picks up an item from Wikidata through wbgetitem, makes changes to it, and then compares it to a specific revision of the item (e.g. the one picked from), the API returns a patch that can then be applied through the wbpatchitem module (not written yet as of creation of this bug).

Version: unspecified
Severity: minor