[Milsurplus] XAP communications teams ?

[Nick England]

May 1945 DNC-21 "General Instructions for Naval Communication Liaison
Officers" concerns comms aboard merchant ships.
I came across ra eference to XAP communications teams - "For certain
invasion and support-invasion movements, special communications teams,
known as XAP teams, ae assigned to some merchant ships."

So does anyone know more about XAP teams?
Cheers,
Nick