"Proprietaries" are also known as "cutouts", and the CIA uses those extensively in order to do things they really aren't allowed to do and to provide plausible deniability. Mike Benz [0] is a good introduction to how the CIA (and, by extension, the state department and Pentagon) work.

I promise "The History of the Intelligence State" is worth your time.

[0] https://x.com/MikeBenzCyber