Users can sign up for Daily, Weekly or Monthly notifications. Notifications always go out immediately after the end of each period. In other words, Daily notifications are sent at around 12:01 AM every day. Weekly notifications are sent out every Sunday at around 12:01 AM. Monthly notifications are sent every 1st of the month at around 12:01 AM. Current server time (as of page load) is: July 7, 2021 9:38 PM.
The Notification portal is here.
When registered users make changes, those are automatically approved. Anonymous (not logged-in) users can make changes, but they are held in a queue waiting for approval. The queues for pages awaiting approval are on this page.
The admins of this site receive an email when a page is first added to any of the ApprovedRevs queues. The notifications are then suppressed until all the queues have been emptied and then a page is added to one of the queues.