As I recall, the E-6 TACAMO’s absorbed the duties of the former Looking Glass plane - now does comms with the sub fleet and CONUS defenses / offensive assets.
As least that’s something I read way back. Gotta love those huge engines on the TACAMO planes.
It takes a big engine to lift the weight (reinforced wings, extra fuel, big transmitter and antenna reel) AND turn the generators.
Yes, they took over Looking Glass.