Mozilla's position from when Chrome first dropped it to September 2024 was "the benefits it provides are not significant enough on their own to justify the cost of adding another raster image format to the Web" [0], which they say is a "neutral" stance. Then like Chrome they only agreed to try it with jxl-rs [1], which is still their present stance. They are a complete passenger in this whole affair, like all other standards, where they basically just copy one side or the other (usually the more conservative side).
It's really bizarre to me that this is presented as "killing the standard". Is Apple also killing mechanical keyboards and hobby electronics development because they're the only ones who don't support Web USB or Web Serial? I strongly prefer having JXL and Web USB/Serial in my browser (FF for the last 20 years), but come on. If we don't like how much power browsers have in software distribution, then maybe software distribution outside of browsers should get fixed.
* [0] https://github.com/mozilla/standards-positions/issues/522
* [1] https://github.com/mozilla/standards-positions/pull/1064
