def get_wm_type(self):
        """
        http://standards.freedesktop.org/wm-spec/wm-spec-latest.html#id2551529
        """
        r = self.get_property("_NET_WM_WINDOW_TYPE", "ATOM", unpack=int)
        if r:
            first_name = None
            for i, a in enumerate(r):
                name = self.conn.atoms.get_name(a)
                if i == 0:
                    first_name = name
                qtile_type = xcbq.WindowTypes.get(name, None)
                if qtile_type is not None:
                    return qtile_type
            return first_name
        return None

        http://standards.freedesktop.org/wm-spec/wm-spec-latest.html#id2551529
        
libqtile/backend/x11/window.py