This adds the main menu track which is called "Geralt of Riva" and is the theme of the Witcher games from the Witcher 3 into Payday 2. It also adds the live background from the Witcher 3 (pre/no dlc version) into the game.
This song can be found here, it was composed by Marcin Przybyłowicz and is part of the Witcher 3 OST

Menu Backgrounds is Required