The current training strategies for LLMs do not also simultaneously build knowledge databases for reference by some external system. It would have to take place

The current training strategies for LLMs do not also simultaneously build knowledge databases for reference by some external system. It would have to take place outside of inference. The "knowledge" itself is just the connections between the tokens. There is no way to tell you whether or not a trained model knows something, and not a single organization publishing this work is formally verifying falsifiable, objective training data. It doesn't exist. Anything you're otherwise told is just another stage of inference on some first phase of output. This is also the basic architecture for reasoning models. They're just applying inference recursively on output.