Thanks for the tip. I was initially embarrassed that I didn't know about this. But it's under My Wikitree/Family Activity Feed" but the family activity feed is already on my Nav Home Page, and gives the appearance of being broken because it misses so much activity that I've been involved in (because it only shows activity from the silly Watchlist, it turns out).
Note to others reading this: I also tested, and confirmed that if I replace my id in the url (after who=) with someone else's, such as my wife, I can see their ancestor activity, too.
Sometime, when I get a little free time, I could imagine putting together an app that combines my watchlist feed, my ancestor feed, and my wife's ancestor feed, dedups them and displays it as a single, unitary feed. Now that would be pretty close to what I was thinking of when I first got involved in this G2G topic. Do you think that would be a good addition to the Browser Extension?