Staff ID as seen from the MS booking API

[shocko]

When listing staff members with the API it returns an object of type staffMember with an attribute named ID.  The API states that ID is:

The ID of the staff member, in a GUID format. Read-only.

is this GUID maintained by Booking somewhere? I would have assumed it was the GIUD of the staff member/user/mailbox user in AzureAD but it appears this is something else. 

[#2]

I've similar doubt. We create staff members under bookings, but where is that object? where can we find it? Can't find it as email address or user account.