This is yet another company that believes the way to finding a good engineer is to try and stump them in the interview process with what I call "tech trivia". It's one thing to try and determine if the interviewee didn't simply make everything up in their resume... but if that's the intent then it would be wiser to ask about specifics on past projects, rather than engaging in the unfriendly sort of questioning that is better suited to a police suspect interrogation than to a process meant to attract talent to your company. Not every great engineer is great at regurgitating information that is easily looked up -- rather, the mark of a great engineer is their thought process and can be determined by looking at their trajectory, and through hands-on technical tests. Unless the job is to have every answer at the ready in a high-pressure interrogation, what they're doing is filtering for people who can withstand this sort of treatment. Which is possibly what they're looking for, quite frankly.