Basically it was a feature that allowed you to find a gun, produce a QR code and then go to their website and “claim” that gun. Basically allowing you to say “I found this first” before anyone else. Kind of a fun way to make loot hunting more rewarding by letting everyone know you discovered a cool gun before anyone else.
I can’t even remember where I got this image, I’ve had it forever. I think it was posted around the time the Underdome was revealed.