Traditional American sweet used to keep up blood sugar while in the toils of heavy card-playing or a day spent watching soap operas. Proper bridge mix is remarkably similar to some kinds of gorp or trail mix, consisting of raisins or other dried fruit, peanuts and/or other nuts, and (usually) some kind of chocolate or licorice, however, nearly every confectioner has an assortment of chocolate-covered fruit, nuts and whatnot under this name.
Peg Bracken calls it "Oddments" in her I Hate to Cook cookbook, and points out that it's an essential component of a home-cooked lunch with the girls: since most women are either "on a diet" or would like to be seen as doing so, yet feel somehow cheated by hospitality that eschews dessert, the only real solution is to include one sweet ingredient in lunch (a fruit salad, chutney, or soup) and put out bridge mix on the card table, living room, or wherever the meeting will take place, offering it around with the coffee.
As Winchester said, I don't fire the guns, I only sell the ammunition.