When the Russo brothers said Avengers: Endgame didn’t possess an end credits scene,they must possess just meant until Marvel took it out of their hands. The film originally screened with nothing more than a hammering sound (harkening back to when Tony Stark built the first Iron Man suit...in a cave...with a box of scraps), but now there’ll be something to shepard MCU fans into the final film of the Phase.
Source: blastr.com