\defaultfontfeatures[CascadiaMono-Light]
   {Extension=.otf,
    UprightFont=CascadiaCode-Light,
    ItalicFont=CascadiaCode-LightItalic,
    BoldFont=CascadiaCode-Regular,
    BoldItalicFont=CascadiaCode-Italic,
    Contextuals=AlternateOff
}