This should be added to the Nightly release notes and at MDN's experimental features page once it lands.

[Why is this notable]: New supported image format.
[Affects Firefox for Android]: yes
[Suggested wording]: Starting with Firefox 153, Nightly builds support the new JPEG XL image format, which generally has better compression than WebP, JPEG, PNG and GIF and is designed to supersede them.
[Links (documentation, blog post, etc)]:
https://jpeg.org/jpegxl/
https://jpegxl.info/
Intend to Prototype

Wording partially taken from https://caniuse.com/jpegxl.

Sebastian

I'd have first checked with authors before requesting docs for them (release managers usually needinfo authors for docs request).

Notably jpegxl.com looks like a random website than having any authority, while jpegxl.info does.

Backed out for causing failures @test_bug496292.html.

• Backout link
• Push with failures
• Failure Log xpc
• Failure Log

(In reply to Kagami Rosylight [:saschanaz] (they/them) from comment #3)

I'd have first checked with authors before requesting docs for them (release managers usually needinfo authors for docs request).

Release managers needinfo feature authors when they see it's missing. Though I often saw features not included in the release notes, because the relnote-firefox or dev-doc-needed flags were missing. So I add thos flags myself when I see them missing.

Though my believe is, authors themselves should be responsible for adding those flags when they turn on a new feature just like they are meant to send an "Intent to Prototype" or "Intent to Ship" for them.
(This also applies to DevTools features, which are currently pretty much always forgotten to be flagged appropriately for the release notes. And I think they deserve more shoutouts.)

Notably jpegxl.com looks like a random website than having any authority, while jpegxl.info does.

Right. I've switched them in my release note comment. Thanks for the hint!

Sebastian

Exactly, and to do so needinfo is better than writing one on their behalfs.

https://hg.mozilla.org/mozilla-central/rev/38c3fcb6e06d

Note added to the Web platform section of our 153 nightly release notes with this wording:

Starting with Firefox 153, Nightly builds support the new JPEG XL image format, which generally has better compression than WebP, JPEG, PNG and GIF and is designed to supersede them.

I am keeping the relnote-firefox? flag set until we include this note in our final 153 release notes, thanks.

The note here was replaced by the note in Bug 2016688 for both Nightly and Beta.

The status of jxl is different on nightly and beta. On nightly it is enabled by default. On beta is it now available to enable, but is not enabled by default. Do the notes handle this?

(In reply to Timothy Nikkel (:tnikkel) from comment #11)

The status of jxl is different on nightly and beta. On nightly it is enabled by default. On beta is it now available to enable, but is not enabled by default. Do the notes handle this?

Yes, we have separate notes between nightly and beta.