Everyone makes up their own. I can't for the life of me fathom how this doesn't subject them to all sorts of discrimination etc. claims (one of the reasons lots of companies favour standardised questions).

Obviously the drawback for FAANG is that standardised questions would rather rapidly leak. Very quickly you'll just end up with candidates that know how to answer your questions.

Where I work now, it's a mix of pool questions ("soft" skills) and interviewer-made questions (technical skills), but it's not a hard and fast rule to use the pool questions. I rarely use the precise wording for the pool questions, and instead adapt them to match the conversation with the candidate.