Update: While the original leak suggested the schematic above showed off a new "M8" motion coprocessor, a pair of knowledgeable commenters at MacRumors believe that the new mystery chip may actually be a barometric pressure sensor. The part is said to be similar to the Bosch BMP280.
Commenter "leecbaker" suggested that the addition of a barometric pressure sensor to the "iPhone 6" could allow for enhanced GPS and indoor/outdoor navigation functions. Other uses would include forecasting weather, better measurement of altitude, and potentially helping to measure users' breathing rates.
The original story published earlier Monday remains in its entirety:
Last year, Apple introduced the M7 coprocessor as part of the A7 system-on-a-chip inside the iPhone 5s, allowing battery-efficient motion tracking. This year's "A8" chip may also feature an improved "M8" motion sensor, according to the latest alleged "iPhone 6" schematic, published on Monday through Geek Bar's Weibo account and spotlighted by G for Games.
While the document doesn't offer any specifics on what upgrades the "M8" might accomplish, GeekBar speculates that the "Phosphorous" chip might help to collect and interpret new health-related data for the next-generation iPhone. Potential subjects suggested include heart rate, calories burned, cholesterol levels, blood sugar and more.
Of course, all of that data can be read into the new Health app included in Apple's next-generation iOS 8 mobile operating system, which will launch next month when Apple is widely expected to unveil its "iPhone 6."
If Apple does indeed have an "M8" in the works, it's likely to be a part of a next-generation "A8" system-on-chip that will power the next iPhone. Some reports have claimed Apple's new custom CPU will be a multi-core design clocked at up to 2 gigahertz.
When the M7 was unveiled last year, observers speculated that Apple could be laying the groundwork for a new tool that could power the company's so-called "iWatch," which is expected to focus on collecting health and fitness data. As such, with an Apple wearable device expected to debut this fall, it's also possible that an "M8" could be a hint of things to come in the "iWatch."
In its current incarnation, the M7 silently tracks user activity in the background. Compatible apps that tap into this data can track a user's steps throughout the day, providing essentially the same functionality as popular pedometers like Fitbit.