I don't know but I can tell you there are all kinds of references and stories about them. To me I think it is real.
Probably the most famous is the one where two of them escort air force one when ozero was in office.(cant find it right now--I found a refernece to it but the video was blacked out)
Supposedly, there was a fleet of 12 in the early 1990's.
We know something went over the Phoenix air space during the Phoenix Lights sightings. That was real. So I'm betting they are real as well.
https://www.godlikeproductions.com/forum1/message959042/pg1?c1=1&c2=1&disclaimer=Continue
Here's a post from above:
The TR-3B vehicles outer coating is reactive to electrical Radar stimulation and can change reflectiveness, radar absorptiveness, and color. This polymer skin, when used in conjunction with the TR-3Bs Electronic Counter Measures and, ECCM, can make the vehicle look like a small aircraft, or a flying cylinder--or even trick radar receivers into falsely detecting a variety of aircraft, no aircraft, or several aircraft at various locations.,P> A circular, plasma filled accelerator ring called the Magnetic Field Disrupter, surrounds the rotatable crew compartment and is far ahead of any imaginable technology.
Anonymous Coward
Supposedly, there is a photo of a TR3B sitting in plain site on the moon. Rumors are you could take a TR3B or G to the moon for lunch and be back for dinner.
https://www.inquisitr.com/2161766/black-triangle-ufo-abandoned-on-moon-by-alien-visitors-resembles-tr-3b-astra-blogger-says/
some interstig stuff on this video:
https://www.youtube.com/watch?v=KChwvXiLGOQ