Firefox takes a Quantum leap forward with new developer edition

Mozilla has developed a new CSS engine, Stylo, that parses CSS files, applies the styling rules to elements on the page, and calculates object sizes and positions. There is also a new rendering engine, WebRender, that uses the GPU to draw the (styled) elements of the page. Compositor combines the individual rendered elements and builds them into a complete page, while Quantum DOM changes how JavaScript runs, especially in background tabs.

Next year, for example, Mozilla will do further work on the browser's sandboxing implementation, incorporating elements from the Chromium project to further restrict its sandbox processes.