So I can't say what the code specifically does or who it's for, but I can talk about how I worked on a c++ engine wrapped in a Java server that was responsible for coordinating a large group of non-homogeneous assets, as well as various architectural details (what libraries did we use, database, messaging setup, etc). So it's not like I have nothing to talk about in an interview, plus the fact that I can't get too specific adds mystique. It's kinda fun, because in my experience there's an assumption most engineers/engineering managers make about what I've worked on from that first statement, particularly if they know where I work, and it's actually not that. :)

So I can talk about architecting a system, about customer feedback and redesigns, but I can’t talk about work I did that will span another three years.

I think at FAANG it’s usually fine — most people have good enough examples even without their full repertoire. But at mid enterprise or F500 companies I could see this being a bit impactful.

Sorry, to be clear, I mean can you give an example of something you couldn't use as an example, but is now public.

I've worked at GAMMA, and agree, it's very doable to turn my work generic and talk about it in-depth, compare it to alternatives, etc. so that was the main driver in asking for an example.