They already responded to FOIA requests, briefed Congress publicly and privately, and announced AARO when they didn't have to. We're pretty well-informed, and Congress has some oversight. It's very ordinary.
The former Deputy Secretary of Defense for Intelligence wrote a blog alleging that there are black projects hidden within DoD contractors that are reverse engineering non-human intelligence craft. He's presented enough evidence to congress for them to add specific legislation to bring these programs to light.