code: public function trans($id, array $parameters = [], $domain = null, $locale = null): string
      {
          // Forward to the default translator
          if (null === $domain || 0 !== strncmp($domain, 'contao_', 7)) {
              return $this->translator->trans($id, $parameters, $domain, $locale);
          }
  
          $this->framework->initialize();
          $this->loadLanguageFile(substr($domain, 7));
  
          $translated = $this->getFromGlobals($id);
  
          if (null === $translated) {
              return $id;
          }
  
          if (!empty($parameters)) {
              $translated = vsprintf($translated, $parameters);
          }
  
          return $translated;
      }
docs: {@inheritdoc}
  
  Gets the translation from Contao’s $GLOBALS['TL_LANG'] array if the message domain starts with
  "contao_". The locale parameter is ignored in this case.