Level-ups now leave a note in your inbox
Earn enough XP and the inbox writes it down. You get a one-time note naming your new rank, with a short description of it and a link to your profile. Lose the XP and earn it back, and the note stays put.
You ship a commit, a moderator approves it, and a new row lands at the top of your notifications. It has a chevrons-up icon, a mono chip reading Lv. 3 · operator, and the line "You reached level 3. Operator." over "System operator with elevated permissions." Click it and you're on your profile.
Credit goes to hbenabdallah, who taught the inbox to watch your XP. A queued check runs after every approved commit, every moderation approval, and every star, once for the author and once for the stargazer, and reads the same XP your profile shows. That is ten per commit, five per star received or reply, two per star given, fifteen per streak day. Level 2 opens at 50 XP, level 3 at 150, level 5 at 1,000, root at 2,500. It runs once per person at a time, so a burst of stars gets one look, and anyone already above level 1 hears only about their current level the next time they earn XP.
One catch. Level-ups only appear under All. There is no Level-ups tab, and Stars, Replies, Mentions and the rest filter the note out entirely, so the proudest row in your inbox hides the moment you click a tab.