We were able to familiarize ourselves with the initial content of the package before, but a small addition to the rental vehicles was added:
-10-day rental of the T26E3 Eagle 7, an American Tier VII medium tank, available for purchase in the Premium Shop with a 20% discount;
-10-day rental of a Chrysler K, American Tier VIII Heavy Tank, available for purchase in the Premium Shop at a 15% discount;
-the other two vehicles are still unknown.
This is the main art of the new Prime Gaming package: 
I got info from prime that loot is not coming