code: public function addPluginType(string $mediaType):bool
      {
          if (!preg_match('#^[-\w]+/[-\w]+$#ui', $mediaType)) {
              throw new MiddlewareException(
                  $this,
                  sprintf(
                      "'%s' is not a valid media type and can not be used as a CSP plugin type",
                      $mediaType
                  )
              );
          }
          if (!in_array($mediaType, $this->tags['plugin-types'])) {
              $this->tags['plugin-types'][] = $mediaType;
              return true;
          }
          return false;
      }
docs: Add a new plugin media type ot the CSP.
  
  @link https://developer.mozilla.org/docs/Web/HTTP/Headers/Content-Security-Policy/plugin-types
  @param string $mediaType
  @throws MiddlewareException
  @return bool