I've just set Ogg Vorbis music tracks and WebM videos to be optional in our content management system. Modern web browsers overwhelmingly support MP3 audio and MPEG-4/H.264 video now, even on Linux, so there's little reason to keep the requirement of including multiple formats around (which slows us down in adding new content). Going forward, all new music tracks will be in MP3 format (and sometimes a lossless FLAC version too), and all new videos will be in MPEG-4/H.264 format.
I intend to remove the Ogg Vorbis audio and WebM video files from Panzer Dragoon Legacy entirely at some point in the future. If you want a copy of these files, please download them soon.