The Mailboxes Layer
This layer focuses on mailbox health. Tests mapped to this layer proactively alert administrators to the over-utilization of user mailboxes, archive mailboxes, and clutter enabled mailboxes. With the help of these tests, administrators can also audit the creation, modification, and deletion of mailboxes. The location of mailboxes and users can also be determined. Additionally, the tests also reveal the recipient types supported by the Exchange Online organization and the count of recipients of each type.
Figure 1 : The tests mapped to the Mailboxes layer