A patch release of Firefox 89.0.2 is available that resolves hangs that occur on the Linux platform when using the software rendering mode in the WebRender compositing system (gfx.webrender.software in about:config). Software rendering is used on systems with older graphics cards or problematic graphics drivers that experience stability issues or can't offload the page content rendering operation to the GPU side (WebRender uses shaders to perform summary rendering operations of page elements).
Source: opennet.ru