What exactly are “the facts evident in the data”? For example if one were to train an LLM on HN comments aside from just learning the syntax of language, the m

What exactly are “the facts evident in the data”? For example if one were to train an LLM on HN comments aside from just learning the syntax of language, the model might be much more useful if there was a way to somehow weight utter dross like the contents of your comment vs comments from domain experts.