I think GP might’ve been referring to the part of Jeff’s post that references GPS, which I think may be a slight misunderstanding of the NIST email (saying “people using NIST + GPS for time transfer failed over to other sites” rather than “GPS failed over to another site”).

The GPS satellite clocks are steered to the US Naval Observatory’s UTC as opposed to NIST’s, and GPS fails over to the USNO’s Alternate Master Clock [0] in Colorado.

[0] https://www.cnmoc.usff.navy.mil/Our-Commands/United-States-N...