diff --git a/includes/class-rest-api.php b/includes/class-rest-api.php
index 292a6c9..c752532 100644
--- a/includes/class-rest-api.php
+++ b/includes/class-rest-api.php
@@ -523,7 +523,7 @@ public static function get_delta( WP_REST_Request $request ): WP_REST_Response|W
 		// tatsächlich verschiedene Zeitpunkte begrenzt statt auf beliebige Varianten.
 		$since_canonical = $since_dt->format( DATE_ATOM );
 		$cache_key       = 'odw_delta_' . md5( serialize( array( $since_canonical, $page, $per_page ) ) );
-		$cached    = get_transient( $cache_key );
+		$cached          = get_transient( $cache_key );
 
 		if ( false !== $cached && is_array( $cached ) ) {
 			$content_type = self::resolve_content_type( (string) $request->get_param( 'format' ) );
diff --git a/tests/test-rest-delta.php b/tests/test-rest-delta.php
index 3a51b01..dd39b2e 100644
--- a/tests/test-rest-delta.php
+++ b/tests/test-rest-delta.php
@@ -725,6 +725,7 @@ public function test_equivalent_since_spellings_share_one_cache_key(): void {
 			$dt = $method->invoke( null, $raw );
 			$this->assertInstanceOf( \DateTimeImmutable::class, $dt, "should parse: {$raw}" );
 			// Mirrors the key derivation in get_delta().
+			// phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.serialize_serialize -- mirrors the cache-key derivation under test.
 			$keys[] = md5( serialize( array( $dt->format( DATE_ATOM ), 1, 20 ) ) );
 		}