Fastest drone in the world? A student built one in a dorm room

That is about all the available material says. It does not give the student's name, the drone's top speed or the test conditions, so the "fastest in the world" label comes with no numbers attached for now. Whether it holds up against the speed records and military systems it is being compared with is something only those details can show.

Why does the Pentagon care about a dorm-built drone?

Drones have become a serious part of modern military thinking, and speed is one of the things that decides how useful they are. A hobby-scale project that beats purpose-built military hardware is exactly the kind of thing a defence department wants a closer look at. The source does not say what the Pentagon actually wants from the student, so that part is still open.