Released overnight on Sunday were the beta versions of Mutter 51 and GNOME Shell 51. This follows GNOME 51 embarking on itsAPI/ABI freeze, feature freeze, and UI freeze a day earlier.

On the Mutter side, one of the notable additions is support for the Wayland ext-background-effect-v1 blur support. This enables background blur effect on apps like terminals and for various other uses.

Also on the Wayland front is support for using the xdg_session_management_v1 rather than their previous XX prefixed private interface, now that the protocol is upstream in Wayland-Protocols. The protocol is used for creating and managing a session for an application.

Also exciting for Mutter 51 are several merges to improve frame scheduling. This work by Michel Dänzer will be interesting to see the resulting performance impact from this improved frame scheduling by the compositor.

Mutter 51 Beta also fixes blurred rendering with non-pixel-aligned monitors. allow for button scrolling on mice, allow external cursor implementations, improved frame scheduling. Mutter 51 Beta now wires up the disable-while-typing timeout setting. Lastly, Mutter is also now able to hide the cursor while input capture is active. More details on the changes for Mutter 51.beta via this commit.

WIth GNOME Shell 51 Beta there is initial support for the "reduced-motion" setting for sensitive users desiring reduced visual motion of the desktop. GNOME Shell 51 Beta also adds SVG-based cursor implementations in the same format that KDE handles its SVG cursors. There is also improved keyboard navigation for the screenshot area selection, support for web login and unified authentication mechanism, and various fixes. Details via this commit

The support for web login and unified authentication mechanism is an interesting one for GNOME Shell 51. It's this merge request from February 2025 over support in the greeter for selecting between multiple authentication mechanisms.