The Cold City Dossier makes no bones about what it is in the product description: "documents that can be used as inspiration for Cold City game, handed out in-game as props..."
And that's exactly what you get, some extremely evocative handouts that can really lend some polish to a game of Cold City. If you're running a con game of CC, printing out the handouts and sticking them into the character dossiers that you give each player immediately gets folks onboard as regards the tone of the game. The handouts are wholly optional though, so this purchase is a nice-to-have rather than an essential purchase.
For a paltry $7 you can't really go wrong with this if you are a Cold City fan.