340
JPEG is Dying - And that's a bad thing | 2kliksphilip
(www.youtube.com)
This is a most excellent place for technology news and articles.
GIMP supports JPEG XL natively in 3.0 development versions. If I remember correctly GIMP 2.10 was released before JPEG-XL was ready, so I think that's the reason. They could have added support in smaller update though, which was the case with AVIF.