code: @Override
      public void startPortletHeaderRender(
              IPortletWindowId portletWindowId,
              HttpServletRequest request,
              HttpServletResponse response) {
          if (doesPortletNeedHeaderWorker(portletWindowId, request)) {
              this.startPortletHeaderRenderInternal(portletWindowId, request, response);
          } else {
              this.logger.debug(
                      "ignoring startPortletHeadRender request since containerRuntimeOption is not present for portletWindowId "
                              + portletWindowId);
          }
      }
docs: Only actually starts rendering the head if the portlet has the 'javax.portlet.renderHeaders'
  container-runtime-option present and set to "true."
  
  @see
  IPortletExecutionManager#startPortletHeaderRender(org.apereo.portal.portlet.om.IPortletWindowId,
  javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)