Covering means that the person is appointed temporarily to cover the duties of another officer who is holding the same appointment but on a permanent basis. Once the permanent appointment holder returns from their period of absence, the covering appointment holder will relinquish the appointment.

Internal means that the person is appointed to hold that position as the main appointment holder (rather than covering for somebody else). But that officer has not cleared the appointment formalities such as cluster interview, or not reached GEO4 yet, or for any other reason cannot be fully appointed yet.