German Empire Cover 1893, 20 Pfennig Reichspost, Prussian Kammergericht Official Mail

Original antique German Empire postal cover from around 1893, franked with a blue 20 Pfennig Reichspost stamp. The cover bears circular postal cancellations, including a Templin backstamp dated 23 February 1893. The cover appears to be addressed to a Königliche Spezialkommission and shows a blue of