I saw the article from elsewhere and I'm actually kind of shocked at the news. It seems entirely unbelievable to the point I have a little trouble comprehending it. I'm skeptical but I won't outright accept or reject the claims until more information is made public. On the surface level the article's claims appear credible, but this is what I would look like trying to dissect or explain it to anyone...

New York Intelligencer Magazine's version of the Debrief article

Debrief article interview "fact-checking" the writer of the OP article

Being of a curious mind, I'm willing to suspend some automatic disbelief for the potential evidence of alien life. We have no information on the nature of what was discovered but kept secret, the size of the vehicles or vehicle fragments, estimations of when said vehicles might have arrived from outer space. The only thing that seems plausible to me at this point, if such vessels were a size that would cause them to burn up completely through our atmosphere, from the ground would look like a meteor, but with sufficient analysis in the sky might determine that they are an "anomalous machine of extra-terrestrial origin" which than was recovered in secret by the military. For all we know now the vehicles/vehicle fragments could just be funny-shaped meteorites. Overall, my expectations aren't high, but it does open up a large number of imaginable possibilities. This might go nowhere, but whatever, it's interesting!