StringTranslationTrait allow to get t() and formatPlural() methods
Example: use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\Core\StringTranslation\TranslationInterface;
class MyClass {
You enable Twig Debugging in sites/default/services.yml.
(If services.yml does not yet exist; copy default.services.yml and rename it to services.yml.)