MLAT is Multilateralization signals. It used Time-difference delays to track planes that aren't transmitting their position. It has nothing to do with the military. (You can filter to just military flights using the "U" -- for U2 -- button at the top of the ADSBexchage map.)

The color coding shows that this is an ADSB track, which is the normal aircraft transponder signal. (If it was an MLAT track, the row would be yellow.) That means that the aircraft is broadcasting it's position. BE20 is the ADSB code for a Beechcraft King 200/ (military desig C-12T-3 Huron), a twin-prop small plane. The ACO code of AE03FB decodes to a USAF plane reg # 84-00143. That's this plane:

https://www.jetphotos.com/photo/7738336

It's a flying Stingray slurping up everyone's cell phone traffic and IDing every cell phone there.

https://infogalactic.com/info/Beechcraft_C-12_Huron

Military traffic - https://www.adsbexchange.com/mlat-beta/

BE20 is the aircraft type. Commonly used by airforce and special services for signals intelligence.