In Firefox builds, which are the basis for the release of Firefox 70, by default, the application of the compositing system for NVIDIA graphics cards on Linux systems with the Nouveau driver and Mesa 18.2 or newer. Configurations with proprietary NVIDIA drivers currently without support for WebRender. WebRender for AMD and Intel GPUs using Mesa 18+ in nightly builds was activated earlier. It is also noted that for WebGL in the nightly builds of Firefox on systems with Nouveau drivers, which was inadvertently disabled in Firefox 68 (the limitation is now only to the proprietary NVIDIA driver).
It is worth noting that the compositing system is written in Rust and offloads rendering operations from the CPU to the GPU. By using WebRender instead of the built-in Gecko engine's compositing system, which processes data using the CPU, shaders executed on the GPU are used to perform composition rendering operations, allowing for significant increases in rendering speed while reducing CPU load.
WebRender is currently only enabled in stable releases for Windows 10 platform with AMD and NVIDIA graphics cards. You can check the activation of WebRender on the about:support page. To force activation in about:config, the settings 'gfx.webrender.all' and 'gfx.webrender.enabled' should be enabled or Firefox can be started with the environment variable MOZ_WEBRENDER=1.
Additionally, it can be noted Testing in Firefox 69 Beta and Developer Edition (currently only in builds for Windows) of the Picture-in-Picture video viewing feature allows users to detach a video into a floating window that remains visible while navigating the browser. To view in this mode, one must click on the pop-up hint or in the context menu displayed by right-clicking on the video, choosing 'Picture in picture' (in YouTube, which substitutes its own context menu handler, you need to right-click twice or click while holding the Shift key).
Source: opennet.ru
