For the last nine months I have been working on a declarative language for VR/AR/MR to display 3D content in a browser. I have called the language XSeen. This work has also been done under the auspices of W3C 's Dec larative WebVR Community Group. XSeen has just gone through a major rewrite and is now on its own site - http://XSeen.org. It includes all of the source material and the use of XSeen on the home page. The source code remains on GitHub. As always the code is dual licensed under MIT or GPL licenses.