I have been relentlessly shilling JPEG-XL's technological superiority especially against their joke of an alternative and a stain on the Internet they call WebP
I designed WebP lossless alone. The rest of the WebP folks added a RIFF header and an artificial size limitation (16383x16383) to match with the size limitation of lossy WebP.
In JPEG XL I believe I had more influence on the lossy ("VarDCT") format than anyone else, but stayed relatively far from the lossless part (except the delta palette, two predictors, 2d lz-codes, and a few other smaller things). I believe Jon and Luca had most influence there.
https://www.reddit.com/r/DataHoarder/comments/1b30f8h/image_...
https://youtu.be/w7UDJUCMTng