Why are there two new ’Microsoft Entra ID’ ’App registrations’ named “DPG secure communication” that I didn’t create?

When adding users to either of the two DPG Office Add-In versions you have installed in ‘Integrated apps’, Azure automatically creates two new App registrations. They are used by Azure for “storing the users”, so to speak.

If you remove one or both DPG Office Add-Ins from ‘Integrated apps’, the App registrations will automatically be deleted.