The Brief: Facts is a term used when agreeing with something, someone, or a statement.

DEEP DIVE
This phrase indicates that someone “completely agrees” with a person or topic at hand, similar to bet. It can also be used to point out something as being factual.
βIf you keep your circle small, the joint comes back fasterβ ππ #facts
— No Way Jose π (@jose_knox) March 23, 2019
It is often paired with a hashtag when used online. Sometimes, the term is used for comedic effect when implying that something not-so-factual is in fact, true.
The older I get the more I understand Noah only allowing animals on the ark. #facts
— Eryn (@tattedwoman95) March 26, 2019