code: public function init()
      {
          parent::init();
          $this->clientOptions = false;        
          
          $options = $this->options;
          $tag = ArrayHelper::remove($options, 'tag', 'nav');
          echo Html::beginTag($tag, $options);
          if ($this->brandLabel !== null) {
              Html::addCssClass($this->brandOptions, 'logo');
              echo Html::a($this->brandLabel, $this->brandUrl === null ? Yii::$app->homeUrl : $this->brandUrl, $this->brandOptions);
          }
      }
docs: Initializes the widget.