Both models of the iPhone 6 were taken apart, revealing that the 5.5-inch iPhone 6 Plus does indeed feature a larger battery.
The iPhone 6 Plus' iSight camera was also examined, and you can even see the camera physically move around thanks to the new optical image stabilization.
iFixIt
Both iPhone 6 models received a repairability score of 7 out of 10, which is an improvement over the iPhone 5S (that phone got a 6 out of 10).
You can take a look at a few more images of the iPhone 6 Plus' internals below, but for the full gallery, head on over to iFixIt.