i'm just getting into the game and upon opening up the light shineth pine box i found a 7 of hearts card. there is no art on the card and the back has a green pattern. it's just like a 7 of hearts you would get from a regular deck of cards. i see no mention of it on the back of the pinebox or inside the story booklet. i'm still learning the game so maybe im missing something obvious. is it supposed to be a token for something?
It's a printer's slip-up. I've seen similar posts about random cards in other games as well. In one case,the added cards appeared to parts of an art poster print.
It's totally a guess, but I think the printers are using random scrap prints they have lying around to serve as dividers when they're sorting and cutting. Sometimes those dividers don't get removed when the decks are assembled.