Could it be that Mansfield has been working on the A11 or 12 chip and that is one of the reasons why Bitcode is being developed?

http://thenextweb.com/apple/2015/06/17/apples-biggest-developer-news-at-wwdc-that-nobodys-talking-about-bitcode/

"A processor independent future?

An anonymous writer on Medium under the name of “Inertial Lemon” believes the changes could signal something larger.

Bitcode is compulsory for Apple Watch apps and but only recommended for use in iOS apps — with it enabled by default “for now” signalling a future requirement.

For the Apple Watch, this means the next hardware iteration could drastically change the CPU and developers essentially wouldn’t know the difference, with the App Store quietly adapting their apps for the new device in the background.

Lemon believes Bitcode could signal a larger architecture change for the Mac. Apple’s Bob Mansfield, who was quietly removed from the executive team but stayed on to work on “special projects,” is one candidate to be working on this.

The company is already producing its own processors for the iPhone, so a switch in the Mac isn’t as crazy as it seems and has been rumored repeatedly in the past.

There’s one sticking point: as far as we know, Bitcode isn’t being supported for OS X apps yet — though we shouldn’t disregard that Wendker, the person who announced the technology at WWDC, works on the OS X team.

Such a change would mean Apple could switch the Mac from Intel to ARM processors and have the majority of third party developer’s apps work on day one, divorcing itself from needing to rely on Intel — a company that is struggling to ship improvements on time — for processors.

It isn’t something that’s going to happen overnight and Bitcode doesn’t necessarily signal such a significant change in the near term.

Eventually Bitcode will free the company up to be far more flexible when it wants to make a drastic change, or at least implement a major new feature in one of its processors. It could mean developers get no warning before the next big shift, allowing Apple to keep it under a shroud of secrecy until the new device is already in stores.

It also should result in far less work for developers the next time such a change comes up. In theory, they don’t need to do anything, though many are suspicious that it won’t be that simple at all."