Fix typing bug

src/MDObjectSyndicationSet.php

@@ -60,7 +60,7 @@ public static function getSearchUrlForObject(string $repo, string $instId, strin
      */
     final public static function checkRepositoryIsKnown(string $repo) {
         if (isset(self::REPOSITORIES[$repo])) {
-            return self::REPOSITORIES[$repo];
+            return $repo;
         }
         return false;