They don’t, and people are way too blasé about how “oh it’s actually the same as googling because it’s just taking from sources online anyway,” when in reality it does nothing to “keep” the knowledge it gets from those sites and is just stringing together words that often go together. It’s like thinking your phone’s predictive text can answer your questions, if your phone also invented quotes and sources (this has already been an issue with journalists and lawyers using ChatGPT to “research”).