\defaultfontfeatures[MonaspaceArgon-SemiBold]
{
  Extension=.otf,
  UprightFont=MonaspaceArgon-SemiBold,
  ItalicFont=MonaspaceArgon-SemiBoldItalic,
  BoldFont=MonaspaceArgon-ExtraBold,
  BoldItalicFont=MonaspaceArgon-ExtraBoldItalic
}