The phrase "exposition dump" refers to a part of a story or movie where a large amount of information or background is given all at once. It is often done in a boring or unnecessary way, making it feel forced and unnatural. Full definition
At times, the dialogue stops and unloads for exposition dumps, and a few of the young cast mates could use some more training back in the land of the Muggles. (metacritic.com)
... The rest of the time, it's all clumsy exposition dumps and self - consciously «streetwise» dialogue, sprinkled with awkward rap references. (metacritic.com)
One of the good bots killed Hitler, we're told in the middle of a particularly weird exposition dump. (southflorida.com)