How is one exposed to tens of millions of lines of unmaintainable code during an interview?
This kind of stuff during interviews is a lot of learning in itself especially if you’re working already in the same area.
Like just as an example, they made sure that by every coffee machine there was a whiteboard for general use. The idea was that if you ran into someone at the coffee machine and got talking and suddenly got an idea together, you could immediately jot it down and geek out about it together and work it out in more detail, right there and then. No meeting to plan, no project manager to involve, just work out your idea together. That's not what you'd expect in a company with lots of managers protecting their little islands.
You ... ask? I've gotten answers like this just by asking in the interview.