As stated on the game’s official YouTube channel:
The Alesso Heist DLC is the 23rd DLC pack for PAYDAY 2 and is a collaboration with the DJ Alesso. Navigate through the Gensec arena, quiet or loud, and keep the show going while trying to crack Gensec’s state of the art exhibition vaults containing loads of cash. The Alesso Heist DLC is designed together with Alesso and features his new song named PAYDAY, adrenaline filled combat and tense stealthing in the home arena of the Starbreeze Suns hockey team. It also comes with the high power and low recoil revolver Matever .357, 4 masks inspired by Alesso’s shows, 4 patterns, 4 materials and 5 achievements.