Firefox 110.0 released

"GPU sandboxing" presumably refers to the Firefox "GPU process", a separate process which performs all GPU API calls (so that e.g. crashes in graphics drivers do not take down the main Firefox process). There are tracker bugs for enabling the GPU process on Linux:

Wayland: https://bugzilla.mozilla.org/show_bug.cgi?id=1732951
X: https://bugzilla.mozilla.org/show_bug.cgi?id=1653444

AFAICT this is all about work that needs to happen in Firefox, there's nothing to be done in Mesa.