I once had a well-known LLM reproduce pretty much an entire file from a well-known React library verbatim.

I was writing code in an unrelated programming language at the time, and the bizarre inclusion of that particular file in the output was presumably because the name of the library was very similar to a keyword I was using in my existing code, but this experience did not fill me with confidence about the abilities of contemporary AI. ;-)

However, it did clearly demonstrate that LLMs with billions or even trillions of parameters certainly can embed enough information to reproduce some of the material they were trained on verbatim or very close to it.