https://caniuse.com/jpegxl

An answer resolves YES if the latest stable build of a browser at the time of market closing contains support for JXL images. Requiring the enabling of a flag still counts (see https://manifold.markets/Rucker/what-browsers-will-have-jxl-image-s#ipiiow9xysl for more details)

Resolves NO otherwise.

Unless specified, OS will not be taken into account. If JXL is supported on one or more OS builds, the browser answer resolves YES. OS specific answers can be made however should be made clear.

Example:

Firefox (Any OS)

Firefox (Android)

Browsers not listed on Can I Use can be added however expect slow resolves since I'm sure as hell not bothering.