So is this another image format I'll download and be unable to use without converting because nothing supports it a la .webp?
Affinity supports it. Photoshop supports it. Microsoft Photos supports it. Gimp supports it. Apple has had systemwide support for it since iOS 17+ / macOS 12+, including in Safari and basically any app that uses the system image functions.
Chromium isn't on the bleeding edge here. They actually were when it first came out, but then retreated and waited, and now they're back again.
WhatsApp doesn't even support WebP though. Hopefully, if they ever get around to adding WebP, they'll throw JXL in, too.
There seems to be some support there, though I tested on iOS 26.
Neither did Apple, which is the problem!
https://apps.microsoft.com/detail/9MZPRTH5C0TB?hl=en-us&gl=U...