$ctx The receipt context. * @return string The subject line. */ public function subject( array $ctx ): string { $store = (string) ( $ctx['store_name'] ?? '' ); $reference = (string) ( ( $ctx['order']['reference'] ?? '' ) ); return sprintf( /* translators: 1: the store name, 2: the order reference number. */ __( '%1$s: your receipt for order #%2$s', 'releasecart' ), $store, $reference ); } }