I think the main point here is that sideloaded add-ons cannot be removed through the add-on manager. Malicious software can still install add-ons silently and without explicit consent, but now the user can view and remove those much more easily.
30 karma · joined June 28, 2015
Edit: The issue is intermittent and it seems to be about displaying badges after the first user on every page; the first user will have their badges displayed correctly while the rest mostly won't.