What is iPad 2,4?

iOS 5.1 beta has just been released to the Apple developer community. Not particularly exciting, no—at least not until 9 to 5 Mac stumbled upon a line of code referencing the "iPad 2,4". Is this a reference to the highly anticipated iPad 3? Not likely. Does it refer to Sprint's upcoming iPad service? Hmm, could be. [9to5Mac]