TheDarkFool
Lord of Altera
As for the "Do Not Delete"s, it's not Belethor, you're right, it's at the Riverwood Trader, in Riverwood, can't remember the guy's name, anyways... No, it's not part of any mod, it's a game obtainable in the vanilla version, it does not normall appear in shops, but every so often you might come across it, they will also appear randomly in the world. I've come across them myself, but here is a video of what I mean.