Mark Gurman, Bloomberg:

Apple Inc., seeking a breakthrough product to succeed the iPhone, aims to have technology ready for an augmented-reality headset in 2019 and could ship a product as early as 2020.

Unlike the current generation of virtual reality headsets that use a smartphone as the engine and screen, Apple’s device will have its own display and run on a new chip and operating system, according to people familiar with the situation.

And:

Apple began putting together a team to work on AR-related projects a couple of years ago, Bloomberg reported in March. Led by Mike Rockwell, who previously ran engineering at Dolby Labs, the group has now grown to several hundred engineers from across Apple, the people said. Scattered across office parks in both Cupertino and Sunnyvale, California, the team is working on several hardware and software projects under the umbrella code name of “T288.”

And:

The new operating system, internally dubbed “rOS” for “reality operating system,” is based on iOS, the iPhone’s operating system. Just as tvOS powers the Apple TV, macOS runs on Macs and watchOS runs on Apple Watches, “rOS” will power Apple’s AR headset. Geoff Stahl, formerly a software manager for games and graphics at Apple, is one of the directors of the “rOS” software group.

Take with a grain of salt, but none of this is hard to believe.