\defaultfontfeatures[CascadiaMono-SemiLight]
   {Extension=.otf,
    UprightFont=CascadiaCode-SemiLight,
    ItalicFont=CascadiaCode-SemiLightItalic,
    BoldFont=CascadiaCode-SemiBold,
    BoldItalicFont=CascadiaCode-SemiBoldItalic,
    Contextuals=AlternateOff
}