Secret military communication?
It's more of a coded military communication or EAM, Emergency Action Message. It was noted several times on the last Q thread. I guess they are put out from time to time but what was unusual about this one was how long the characters were on this particular communication.
Some claimed potentially big things happen when you see a large communication like that from an EAM. Just more to be determined and here is more info about them:
https://www.numbers-stations.com/military/usa/hfgcs/
CGato