Odd, are you trying this as an admin user? What version of persona and nodebb?
Yes - trying as admin. Latest versions of NodeBB and Persona
On Settings → Notifications, what is it used for? I have tried entering text, and a link and could not notice anything happening.
It creates a notification for the user when they register. The text is what is displayed, the link is where the notification goes when they click the Notification.
@a_5mith, thank you. Those two sentences (modified to fit the context) should be added to that screen.