Okay, this is somewhat persnickety.
Notifications of changes in the reputation, activity, responses, and favorites categories are indicated by this blue "bullet":
The changed or added items within the tabs have a slightly different background color, (
#FFFFDD1), which looks like this:
Except for those on the favorites tab, which just have the plain white background.
Could the different background color be added for changed favorites?
1) For clarity purposes, I changed the different background color in the image above to