What does "archived" user notification mean?

Issue

• At System Settings/User Notifications there are some settings related to user notifications, more precisely to so-called "archived" user notification events (see attached screenshot)
• But it is not clear what this means, what "archived" means exactly in this context

Environment

• 7.3

Resolution

• "Archived" here means simply "read", a notification that has been read (opened or marked as read by an end user)
• Technical background: see the archived column in the usernotificationevent table