I should be able to see "diffs" when looking at an Update

(User Story, Investigate , Priority: Critical, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284oe not found, )
Publication
Summary: That is, I want to be able to see exactly what changed, with some context.
This probably requires a good XML diff'er. From my initial research, it looks like I may have to write this myself.