The lossless thingy is Brunsli. In the last meters of the standardization, Brunsli in JPEG XL was replaced with "Brunsli 2.0", the more natural formalism in JPE

The lossless thingy is Brunsli. In the last meters of the standardization, Brunsli in JPEG XL was replaced with "Brunsli 2.0", the more natural formalism in JPEG XL format, allowing for a smaller spec and decoder as well as parallel decoding. Guetzli is a slow high quality jpeg encoder. One can use jpegli for that need nowadays, 1000x faster...