Mozilla Firefox 121 has been released, and Linux Wayland users will be particularly interested. The Firefox Snap now runs in Wayland mode by default for the Ubuntu 23.10 release. Mozilla has decided to extend this to all Linux users who use Wayland. This move is significant because Wayland offers better graphics performance, non-blurry rendering on HiDPI displays, and support for touchpad and touchscreen gestures. Additionally, Wayland is the future for secure and performant display server needs on Linux. Firefox 121 also includes other notable changes such as support for Voice Control commands on macOS and bug fixes for Linux-specific issues. Overall, this update improves the Firefox experience for Linux users.
https://www.omgubuntu.co.uk/2023/12/firefox-121-released-now-defaults-to-wayland-on-linux