Most notably is the experimental Variable Refresh Rate (VRR) support that was merged on Saturday after obtaining a feature freeze exception. The GNOME 46 desktop thus will be able to leverage the experimental VRR support with capable Adaptive-Sync/FreeSync displays!
Also exciting with the Mutter 46.rc release is unifying Wayland pointer and keyboard grab mechanisms, modifier-aware screencasting, fixing a synchronization issue under the X.Org environment, sending fractional scaling events immediately on window creation, and then a lot of bug fixes and other changes.
The unifying of Wayland pointer and keyboard grabs should fix various drag-and-drop issues, dismissing popups with tablets and touch if clicking outside the app will now work, and other "longstanding bugs" under Wayland should be cleared. The modifier-aware screencasting support meanwhile now enables DMA-BUF screencasting support on NVIDIA hardware.
More details on the Mutter 46.rc changes via this commit .
Also released minutes ago was the GNOME Shell 46 release candidate. The GNOME Shell 46.rc fixes repainting the drawing area, supporting locking down the extension installation, notification improvements, on-screen keyboard improvements, support for using H.264 encoding for screencasts if available, working around an issue with NetworkManager's WireGuard support, a crash fix, and various other bug fixes and code clean-ups.
The GNOME Shell 46.rc changes are outlined here . The GNOME 46 release candidate will formally be announced in the coming days. The GNOME 46.0 stable release is expected on 20 March.