What is the Backrooms movie about? Explaining the lore and history of the internet’s strangest horror ecosystem

The somewhat familiar, seemingly infinite liminal expanse that is the Backrooms is, unto itself, a rather interesting story. Similar to the Slender Man before it, the Backrooms was born out of a single internet post that has slowly and effortlessly ballooned into a franchise all its own, to the point where the new Backrooms movie is now poised to give The Mandalorian and Grogu a run for its money.