I think they made those with new Reddit ten years ago. Every user has one. I don't remember what the idea was.

I think this has always been there for every user. So that you can have your personal profile. Don't think it was widely used.

If /u/user posts something to their Reddit profile, it's actually posted to /r/u_user.

Normally this isn't visible, but if a user account is deleted their profile sub might still exist.

Sorry my screenshot didn't load and imgur is glitching. Now getting a syntax error from lemmy.