Get a list of shared mailboxes that are accidentally licensed

We know that in a hybrid scenario or during migration all shared mailboxes are migrated as a user account and then converted in a shared mailbox.

Sometimes admin forget to remove the license for the shared box after conversion and there is no GUI alternative to see if the shared mailbox is licensed. Shared mailbox in Office365 do not require a license.

To find out what shared mailboxes are “accidentally” licensed: