The OpenType Font File specification recommends that "Collection fonts that use CFF or CFF2 outlines should have an .OTC extension." mpv should accept .otc as a fallback extension for font detection should the mimetype detection fail.
The OpenType Font File specification recommends that "Collection fonts that use CFF or CFF2 outlines should have an .OTC extension." mpv should accept .otc as a fallback extension for font detection should the mimetype detection fail.