I've had something similar happen but I was actually hired. One of the rounds was with a super senior CTO-like type, and they questioned me about low level details of building Linux CLI tools, which is something I've never done or really didn't know anything about.
I think the idea was to pick an area the interviewer was super familiar with, and see how you can handle stress, can you say "I don't know", can you make some guesses even in the space you are not familiar with and so on. Is it the most effective way of doing interviews? Probably not. But it's not a terrible screen either for common pitfalls with senior engineers.
I think the idea was to pick an area the interviewer was super familiar with, and see how you can handle stress, can you say "I don't know", can you make some guesses even in the space you are not familiar with and so on. Is it the most effective way of doing interviews? Probably not. But it's not a terrible screen either for common pitfalls with senior engineers.