Activity preview: want to compare before/after, not compare with current version

Describe the feature
While working on a demo of FW Lite, I was making many changes to a single entry. I found that while the comparison of "Here's how the entry looked after the change" vs. "Here's how the entry looks now" was useful, what I often wanted was the kind of diff I would get out of Git: "here's how it looked before the change" vs "here's how it looked after the change".

Maybe our diffs don't store that information, and we would have to reconstruct the entry by replaying commits since a snapshot in order to present the "before" view. So this might be a "big ask". But the "what changed?" model seems to be slightly more useful than the "What did it look like back then, and what does it look like now?" model.

Or that just might be my bias towards the tooling I'm familiar with, where I can easily do git log -1 -p (hash) to see what changed at a point in time. Maybe when I talk to users I'll find that they would prefer to have the feature in its current state, comparing the state after a change to the current state. If so, I'll update the request accordingly.

Who is this feature for?
Users

Pages affected
Activity view

Start with the Activity view named in the issue and trace how its current comparison is represented and where diff history is stored. Done would mean users can compare an entry before and after a change, rather than only comparing the changed state with the current state.