The format audio/mp4 is working fine: https://iiif.io/api/cookbook/recipe/0002-mvm-audio, but this is not the right media type for mp3, that is audio/mpeg, but it does not work anymore in uv4 (worked in uv3).

v3: https://uv-v3.netlify.app/#?manifest=https://bibnum.explore.psl.eu/files/tmp/mp3.manifest.json
v4: https://uv-v4.netlify.app/#?manifest=https://bibnum.explore.psl.eu/files/tmp/mp3.manifest.json