Arbitration mailboxes made their appearance in Exchange 2010 as a special form of mailbox that is designed to be used by Exchange itself rather than a user. In short, there are times when Exchange needs to stuff data away for one reason or another and it makes sense to use a mailbox for this purpose. After all, mailboxes go in databases and can be protected by high availability, and so on…
The full set of arbitration mailboxes is exposed in all its glory by running the command: