Notifications
The bell in the header carries anything the Editor needs to tell you about — in practice, the outcome of a lemma review request. A badge shows the unread count.
Reading them
Opening the bell lists your notices, unread ones marked. Opening the panel does not mark everything read: a rejection carries the reviewer's note, and clearing it on sight would lose the one place that feedback appears. Click a notice to mark it read, or Mark all read to clear the badge.
Read notices stay in the list, so an approval from last month is still there after the badge has gone.
Nothing yet. means what it says.
When the count refreshes
Unread counts are fetched when you sign in and again whenever you return to the tab, so a session left open all day stays current without a reload.
For administrators, the same refresh updates the red dot on the wrench — the count of lemma requests waiting in the review queue.