We must show how others have changed the work that interests us. Solutions here should handle more than just pair-wise differences.
Item specific history could be shown on hover. We could extract the relevant actions from the journal. Forks don't apply to items but the flags from forks could be spread underneath every action making authorship clear. Hover over these actions could invoke item type specific diffs.
Journal hover should retrieve the version as well as scroll to change as it does now. Again there is opportunity for item type specific diffs.
Hovering over twins should tell us something about how it is older or newer.