Standalone headsets, like Microsoft's Hololens or the Vive Focus, are essentially wearable computers. Although designed specifically for standalones, Firefox Reality can also run on headsets that plug into a PC for resources and low-end devices like cardboard viewers as well as desktops, laptops, tablets and smartphones.
Firefox Reality is in development by the open source community under the auspices of the Mozilla Foundation. The browser is based on the same web technologies as other versions of Firefox, along with Servo, an experimental browser engine.
Mozilla introduced Firefox Reality in April 2018. The Foundation initiated the project to further the integration of browser-based VR, AR and MR applications for the immersive web.
Watch an early preview of Firefox Reality: