I wonder how hard it would be to write a non-compliant SoundFont that uses Opus - Ogg Vorbis is very old at this point and not as good as newer codecs.
SF3 is "just" Ogg compressed SF2, but there's no spec and it seems like it's only implemented in http://www.fluidsynth.org/
Edit edit: in the SF2.04 spec - "hydra - A. A nine-headed mythical beast. B. The nine “pdta” sub-chunks which make up the SoundFont articulation data."
Edit: that was a fun rabbit hole
SF2.04, owned by Creative. http://freepats.zenvoid.org/sf2/sfspec24.pdf
SF3 is "just" Ogg compressed SF2, but there's no spec and it seems like it's only implemented in http://www.fluidsynth.org/
Edit edit: in the SF2.04 spec - "hydra - A. A nine-headed mythical beast. B. The nine “pdta” sub-chunks which make up the SoundFont articulation data."