Athat will on the Firefox 94 release to change has been new rendering backend by default for graphical environments that use the X11 protocol. The new backend is notable for the use of the interface for displaying graphics instead of GLX. The backend supports the open source Mesa 21.x OpenGL drivers and the proprietary NVIDIA 470.x drivers. AMD proprietary OpenGL drivers are not yet supported.
The use of EGL solves problems with gfx-drivers and allows you to expand the range of devices for which video acceleration and WebGL are available. Previously, to activate a new backend for X11, it was required to start with the environment variable MOZ_X11_EGL, after installing which Webrender and the OpenGL compositing components switched to using EGL. The new backend is prepared by splitting the, originally created for Wayland and allowing direct output frames to GPU memory, which can be reflected in the EGL framebuffer and rendered as a texture when flattening web page elements.