Take a look at some super-shiny gold & ceramic, which turns out to be a high-bandwidth parallel data acquisition system.  There's a lot of fast op-amps, comparators, and ADCs, plus a dynamic offset-correction circuit with a specialty sample-and-hold chip, but the overall function is still a bit of a mystery (I suspect either imaging or radar).

https://www.eevblog.com/forum/projects/reverse-engineering-some-litton-military-boards/