code: public OSFamilyEnum getOsfamily() {
      if (isReference()) {
        final TargetDef refPlatform = (TargetDef) getCheckedRef(TargetDef.class, "TargetDef");
        return refPlatform.getOsfamily();
      }
      return this.osFamily;
    }
docs: Gets operating system family.
  
  @return os family, may be null.