What does the Notification “badge” on MacOS System Preferences icon really mean?

It turns out that Apple really wants you to take security seriously (you should!) and is promoting the use of Two-Factor Authentication (2FA) for iCloud accounts.

If you click on the iCloud icon, you will be presented with the message which was the notification source:

If you hit the “Continue” button you will be presented with the opportunity of enabling 2FA, learning more (please do this at least), or leaving it off for now.