As noted by MacRumors, the unique "iPad3,6" designation points to a new version of the current 9.7-inch iPad, which carries the "iPad3,1," "iPad3,2" and "iPad3,3" naming scheme for existing iterations of the device, and not the much-rumored "iPad mini."
While mere speculation, the unknown device could be a slightly tweaked third-generation iPad with Lightning connector support, possibly meant to bring parity to the full-sized tablet's charging system and Apple's recently-released iPhone 5 and upcoming iPod products.
In August, a separate report found a pair of iPads in a developer's access logs bearing the "iPad2,5" and "iPad2,6," designations thought to be the identifiers of Apple's rumored 7.85-inch "iPad mini."
While not entirely out of the realm of possibility, the iPad mini is not expected to use an A6-based chip and is thought to instead leverage a variant of Apple's A5 series found in the iPhone 4S and iPad 2. The small form factor tablet is widely believed to carry a non-Retina display, meaning it won't require the same processing power as the third-generation iPad, which itself uses a modified A5 chip.
Apple is expected to debut the 7.85-inch iPad sometime this October, however there has been little information regarding an updated third-generation iPad.