This is also needed to work around bad design at times - like a NAS device with a web interface which when its certificate has expired still requires you to update it via that same web interface if you forgot to enable SSH access in the configuration...
That's too late I believe - at least both the Palemoon and Thorium browsers already support JPEG-XL. Firefox could be the first major browser to support JPEG-XL om Linux, which would be really nice.
As far as I understand, the flag only works in the "nightly" development releases, not (yet) in the regular releases of Firefox. Support for JPEG-XL in the regular versions of Firefox would be very nice and I think there are patches from e.g. Palemoo...
+1From an authoring perspective JPEG XL makes much more sense and it's important to see the benefits from a broader perspective than just last-mile content delivery to the browser (even if progressive decoding is a major benefit even there).
