Today on YouTube, MacRumors published a video that seems to feature a fully assembled iPhone 6S booted up with a simple gear icon in the middle. The supposed phone doesn't boot into iOS, so this is probably Apple's test software. Other pictures of the internals have also leaked which appear to feature updates and changes compared to the current generation. You can view the video below, which features an unnamed individual peeling off a piece of film from the phone's screen, then displaying the gear icon in the middle of the screen while lifting the display from the rest of the body.
As 9to5Mac has reported, "Several images published alongside the video show the internals in greater detail. The first image claims to reveal the logic board for the new handset (top). The iPhone 6S was already revealed to use the Qualcomm MDM9635M LTE modem for increased data speeds. In the new photo, the it is also shown as having a Qualcomm WTR3925 RF chip (highlighted in red). The relevant section of the iPhone 6 board is provided alongside it for comparison.
"A second image shows the unlabled A9 processor (left) compared to the A8 processor found in current iPhones. The A9 chip will be produced by Samsung and will reportedly come with 2 GB of RAM, though these pictures don’t confirm that.
"The final image shows the inside of the display, which is rumored to support Force Touch, though again, these images don’t do much to prove that rumor. Images of the display panels with support for Force Touch have previously been leaked."