Is the Gold DLC for Sniper: GW2 a collection of all the other downloads or what?
Your guess is as good as mine. While not the most useless DLC description that Microsoft has ever come up with (that goes to "Please download this content"), they still successfully manage not to describe the DLC at all.
EDIT: As Sniper Ghost Warrior Gold on Steam included the game and all of the DLC, I'm going to assume that the Gold Pack for this game includes all of the DLC with the exception of the free multiplayer expansion pack. The file size certainly suggests that this would be the case anyway.