Mozilla has always been on the frontlines of virtual and augmented reality (see our work with WebVR, WebAR and A-Frame), and this is a mixed reality browser that is specifically built to tackle the new opportunities and challenges of browsing the immersive web.
Me, in April 2017:
The way information is displayed is going to dramatically change within MR applications. How should a Wikipedia page on the honey bee be shown to a child wearing MR glasses while they are touring an apiary? Certainly this new wave of information layout should not be constrained to the resizable “windows” that we see in current demos but that we will see a rich set of layout and display tools that will make mundane information that the web currently hosts to come alive.
Mozilla sees this and they are skating to where the puck will be.