This is a pretty common situation in the US for folks who work on government contracts.

Yup. I’m outside DC. Somewhere near half my software engineer (and adjacent fields) friends are under contract to either the military or NSA/CIA. Most of them with TS/poly clearances. Ask one of the what they’re working on and the most you’ll get is something like “dig data on platform X”.

If platform X is something public, they could talk about the platform. But, talking about any project specifics, implementation details, etc would be a felony.

thank god they keep it all secret, otherwise our military might be defeated in a 20 year long war against illiterate peasants.

oh wait.

NDAs don't care where you sourced your knowledge from.

Im pretty sure I learned a full set of new skills at my current job.

I don't think knowledge on any particular api is particularly useful compare to the more generic "can you read docs and use apis" skill, which is directly applicable from something like high level hard ware work making an ftdi USB chip go brrr to making dynamoDB work nicely, but I definitely didn't know anything about dynamodb before doing a server/web job

Async distributed systems and FPGA vhdl have some overlap in how you build things, but doing an interview based on my old FPGA skills likely won't show much of my servers and databases systems design skills