Put this code at the end of your local development settings file (/web/sites/default/settings.local.php)
// Include Kint class.
include_once(DRUPAL_ROOT . '/modules/contrib/devel/kint/kint/Kint.class.php');
// If debugging is very slow or leads to WSOD reduce the number
// of levels of information shown by Kint.
// Change Kint maxLevels setting:
// Set the maxlevels to prevent out-of-memory. Currently there doesn't seem to be a cleaner way to set this:
Kint::$maxLevels = 5;