https://en.wikipedia.org/wiki/Joint_Photographic_Experts_Group#JPEG_XL:
The current target publication date is October 2019.
Early but could be nice.
+1
I'm using Google Canary v89 and Firefox Nightly v85, I can view JPEG-XL files in these browsers no problem!
Sample image in browser: https://res.cloudinary.com/demo/image/fetch/f_png/https://res.cloudinary.com/demo/sample.jxl
https://cloudinary.com/blog/cloudinary_supports_jpeg_xl
Please can the team add JPEG-XL live now.
https://res.cloudinary.com/demo/image/fetch/f_png/https://res.cloudinary.com/demo/sample.jxl
is not a valid test as it returns a PNG, mentioned in the URL and accordingly are the response headers.
https://res.cloudinary.com/demo/sample.jxl
doesn't work for me in Chrome Canary 89.0.4333.0 nor Firefox Nightly 85.0a1
Issues:
@Schweinepriester
Why can I save .jxl files in Google Canary?

I'm pretty sure they have a fallback setup using .png which you are seeing.
But for me, I'm seeing the .jxl and can save it in Google Canary.
Also your Chrome tracking bug seems wrong.
Chrome Status: https://www.chromestatus.com/features/5678152091172864
Chrome Issue: https://bugs.chromium.org/p/chromium/issues/detail?id=1109698
That's rather childish adding a dislike when I added the correct links to the chrome tracking:

I'm using Google Canary v89 and Firefox Nightly v85, I can view JPEG-XL files in these browsers no problem!
Sample image in browser: https://res.cloudinary.com/demo/image/fetch/f_png/https://res.cloudinary.com/demo/sample.jxl
https://cloudinary.com/blog/cloudinary_supports_jpeg_xl
Please can the team add JPEG-XL live now.
Sorry for the confusion, but that url creates a PNG file (that's what the f_png does), even though the 'extension' at the end of the url is .jxl.
If at some point this url: https://res.cloudinary.com/demo/sample.jxl
can be displayed by your browser, your browser supports JPEG XL.
Chrome does not support jxl yet, not the subset that can be used as content-encoding for jpeg and also not the full format.
JPEG XL is currently at version 0.1, which is a "format release candidate". When version 0.2 is reached (which will be the "format release"), the codec will be stable enough to start talking about browser support, since at that point the bitstream is stable enough to guarantee that files will remain decodable. This should happen soonish (in a week or two, I hope).
@jonsneyers Thank you, your comment makes sense.
JPEG XL is in FDIS stage now in the ISO standardization process. The bitstream has been frozen for a month now. This is a good time to start talking about browser support.
I support the inclusion of JpegXL!
Chromium merged issue 1056172, so https://bugs.chromium.org/p/chromium/issues/detail?id=1178058 appears to be the new tracking issue.
Currently there are now two chrome status entries:
The former appears to be a sub-feature while the latter seems to be for displaying JPEG XL images.
At this rate browsers will support JPEG-XL before caniuse does.
Now available at https://caniuse.com/jpegxl
For the record, I generally see if browsers are actually interested in supporting a feature before adding it, especially in the case of new file formats. In this case it's still pretty early but it does seem like they're planning it for Chrome.
Chrome is preparing support for JPEG XL.
Add libjxl library and its dependencies.
Make the new "libjxl" library available in gn build system and
include its new dependencies (google/highway).This library is now included in the build from the
blink_platform_unittests_sources target so it is built in this
commit. Since it is only in the unittest it won't be included in
chrome binary with this commit.This library will be conditionally included behind a flag in a
follow up commit in preparation to support jxl Content-Encoding and
image/jxl codec.
Most helpful comment
JPEG XL is in FDIS stage now in the ISO standardization process. The bitstream has been frozen for a month now. This is a good time to start talking about browser support.