Patch 10.0: Kobolds Flavor Text, New Quests, Kobolds Brawl, 5 Card Backs, Datamined Info
Hearthstone - Azeroth is Burning Card Back
Hearthstone added a new card back in today's patch and it is in the same category as the Warlords of Draenor Collector's Edition card back. It is listed as being acquired from a special promotion. You can see the rest of the patch notes on Hearthpwn.