Some are specialized, some are diversified. Definitely public, I believe they all have to be listed on fedgov's contractor list? Some are obvious weapons contra

Some are specialized, some are diversified. Definitely public, I believe they all have to be listed on fedgov's contractor list? Some are obvious weapons contractors, some aren't (like extensions of big-name universities). If you see job listings for weapons development, cyber ops, secret-clearance software dev, cryptography, etc, that's a clue.