Their standards position is still neutral; what switched a year ago was that they said they would be open to shipping an implementation that met their requirements. The tracking bug hasn't been updated[2] The patches you mention are still part of the intent to prototype (behind a flag), similar to the earlier implementation that was removed in Chrome.

They're looking at the same signals as Chrome of a format that's actually getting use, has a memory safe implementation, and that will stick around for decades to justify adding it to the web platform, all of which seem more and more positive since 2022.

[1] https://mozilla.github.io/standards-positions/#jpegxl

[2] https://bugzilla.mozilla.org/show_bug.cgi?id=1539075