Fixing an old bug, I went ahead and made the diff links in the "classic" Recentchanges view include the oldid numbers, so they show specifically the diff for the edited item. (We get the information provided for us already in our read of the recentchanges table.)
For extra points, this prevents the slowdown when someone selects the last diff of a page with many revisions.
-- brion vibber (brion @ pobox.com)