Sorry in my first post I wrote that it should be
X-KDE-Solid-Predicate=[ StorageVolume.ignored == true AND OpticalDisc.availableContent == 'Audio' ]
but this doesn't work, it should be
X-KDE-Solid-Predicate=[ StorageVolume.ignored == true AND OpticalDisc.availableContent & 'Audio' ]
Sorry in my first post I wrote that it should be
X-KDE-Solid- Predicate= [ StorageVolume. ignored == true AND OpticalDisc. availableConten t == 'Audio' ]
but this doesn't work, it should be
X-KDE-Solid- Predicate= [ StorageVolume. ignored == true AND OpticalDisc. availableConten t & 'Audio' ]