code: public CmsSitemapData getSitemapData() {
  
          if (m_sitemapData == null) {
              try {
                  m_sitemapData = CmsVfsSitemapService.prefetch(
                      getRequest(),
                      getCmsObject().getRequestContext().getUri());
              } catch (CmsRpcException e) {
                  LOG.error(e.getLocalizedMessage(), e);
              }
          }
          return m_sitemapData;
      }
docs: Returns the needed server data for client-side usage.<p>
  
  @return the needed server data for client-side usage