Case C-23/21: Order of the Court (Sixth Chamber) of 23 September 2021 (request for a preliminary ruling from the Gericht Erster Instanz Eupen — Belgium) — IO v Wallonische Region (Reference for a preliminary ruling — Article 99 of the Rules of Procedure of the Court — Article 49 TFEU — Freedom of establishment — Road traffic — Driver resident in one Member State — Vehicle registered in another Member State — Vehicle made available to the partner and manager of an undertaking established in that other Member State — Registration obligation in the first Member State)