Fatal error: Uncaught Error: Class "Drupal\Core\Controller\ControllerBase" not found in /home/qcsvlel/www/core/modules/block/src/Controller/BlockLibraryController.php:18 Stack trace: #0 {main} thrown in /home/qcsvlel/www/core/modules/block/src/Controller/BlockLibraryController.php on line 18