Added to the Wayland Protocols repository back in May of 2025 was the ext-background-effect-v1 protocol for background blur that had been under discussion since early 2024. The initial focus is on being able to apply a blur effect on a window's background or otherwise a specified screen region. GNOME 51 has now merged support for ext-background-effect-v1 with the latest Mutter code.

Plasma 6.7 added ext-background-effect-v1 for background blur on Wayland. Following the latest GNOME 51 Alpha release, Mutter has now landed its ext-background-effect-v1 support.

The ext-background-effect-v1 support authored one month ago by Kristof Imerir allows for exposing the blur capability to Wayland clients under Mutter. This is useful for apps/toolkits wanting a "frosted glass" like effect on windows.

More details on this addition merged to Mutter Git on Friday can be found via this merge request, which includes a demo video of the effect in action.