Just noticed this weird little thing, at least on iOS Safari - It looks like the country flags over avatars only show up after you preview a profile. For example, open a thread and look at the avatars for all the posters - they’re all just the avatars of the users. Then view the profile preview for any user (click their name in iOS; maybe hover over it on desktop?). After that, all of the users on that page have country flags overlaying their avatars.