Reportedly, internal builds of iOS 13 contain an app that puts the iPhone screen into a head-mounted stereoscopic mode. The documentation, according to MacRumors, points at two modes: "worn" and "held".
A text file in the release talks about an augmented reality shell for stereoscopic AR apps called "StarBoard" and speaks about a device codenamed "Garta". The internal iOS 13 beta code is also packed with references to StarBoard, including strings like "ARStarBoardViewController" and "ARStarBoardSceneManager."
With speculation of a potential reveal next week! Looks like the 2020 rumour could be true. I can see the "20 20 vision" headlines now