The first few minutes of a first date typically consist of expository chit-chat, meaning that that's when people fill each other in on the basics: where they're from, what they studied in school, and what they want to be when they grow up. It's background info.

A synonym for expository is explanatory. It might help to relate the words, as expository dialogue usually exists to give the audience an explanation of a character's previous actions. The challenge for a playwright is to communicate exposition by crafting expository dialogue that isn't boring. It's often a sign of amateur writing when the expository information stands out as just that. The experienced writer can hide the expository information inside the action and other speeches.

Definitions of expository

adj serving to expound or set forth

“clean expository writing”
informative, instructive
serving to instruct or enlighten or inform