From the campaign:
Backstory Cards blend your characters and setting concept into an intriguing set of relationships and history. It’s tailor-made for games where the player-characters already know each other—from fantasy adventurers to star marines, from supernatural beings who share the same city to global-hopping troubleshooters.
This deck of cards works well with most roleplaying games, including GM-less ones. It also includes how to directly integrate Backstory Cards into Fate Core and Fate Accelerated's character creation.