Bottom line: Apple's upcoming mixed reality headset will be driven by a custom operating system known as realityOS, developers have discovered. The naming scheme makes sense, at least on paper, as Apple has given similar names to its other operating systems including iPadOS and watchOS.

References to the operating system, reportedly codenamed Oak, were found in App Store upload logs and open source code.

Bloomberg's Mark Gurman in a 2017 report said Apple was developing a custom operating system for its headset called rOS, short for reality operating system. In a follow-up story in 2020, Gurman said Apple wanted to create its own App Store for the platform "with a focus on gaming and the ability to stream video content, while also serving as a sort of super-high-tech communications device for virtual meetings."

Apple planned to debut its first headset in 2021 and ship it this year, but ran into design challenges. Sources said engineers are having issues with the device's camera and software, and are also grappling with heat dissipation issues.

The headset is expected to be powered by a pair of high-end, M1-style chips and allow users to seamlessly switch between AR and VR modes.

As always, it's important to approach rumors like this with a healthy dose of skepticism and remember that nothing is official until it comes from the horse's mouth. That said, those reportedly close to the project claim Apple is now targeting this year's WWDC in June to unveil the project.