They're not due in the US until tomorrow, but it's already tomorrow somewhere in the world, and that somewhere is Australia. Well, that didn't make any sense, but the point is that some blokes at Sydney, Australia-based iExperts got their hands on some brand new iPhones and did a teardown before the guys at iFixit were able to do the same.
As usual, the devices are locked down with Pentalobe screws and require the use of a suction cup to remove the screen. The team noticed that there's a special cable that connects the Touch ID sensor on the iPhone 5s to the charging port assembly -- not sure of the reason, but I'd speculate that it's for grounding the sensor when the iPhone is docked and charging.