Fatal error: Uncaught Error: Class "Drupal\Core\Form\ConfigFormBase" not found in /home/qcsvlel/www/core/modules/locale/src/Form/LocaleSettingsForm.php:15 Stack trace: #0 {main} thrown in /home/qcsvlel/www/core/modules/locale/src/Form/LocaleSettingsForm.php on line 15