According to code uncovered by 9to5Mac, macOS Sierra will support USB 3.1 Gen 2, better known as the upgraded version of USB-C. Apple introduced USB-C ports into its lineup with the 2015 Retina Macbook, and it's a safer bet than ever that those ports will be coming to the new Macbook Pro.
The code 9to5Mac found shows that Apple is planning to support the upgraded USB-C from a software side. Given that the Retina Macbook isn't due for an update for a good six months, and a Macbook Pro refresh has been overdue for some time, it's a safe bet that this code is aimed at the upcoming Macbook Pros.
Many will probably be disappointed if the new Macbook Pros ditch conventional USB ports entirely, but adding USB-C connectivity could be a major boost. The ports should have the capability for 10Gb/s transfer speeds, which means that one port could potentially handle a high-resolution external display, talk to an external graphics card, and provide power all in one.
Based on history, Apple has always been swift in bringing the latest USB and Thunderbolt ports to its Mac devices for maximum performance. Thus, the addition of the 10Gb/s variant of USB 3.1 does not come as a surprise. The same thing can be said of Thunderbolt 3, which is also rumored to be part of the MacBook Pro refresh this year. Thunderbolt 3 would be a great addition to the Mac device’s hardware, since it supports both the 10Gb/s USB 3.1 and the DisplayPort 1.2.
Almost two weeks ago, it was revealed that the MacBook Pro 2016 will likely come with a small touchscreen OLED display that would replace the top functions keys on the keyboard of the laptop. This claim is already backed by codes found in the macOS Sierra, as noted by 9To5Mac in a separate report.
There is still no word on the possible release date of the MacBook Pro 2016, but some sources are claiming that Apple will mostly launch the new laptop this October or November — possibly the same time as the official release of the macOS Sierra update.