code: private void initXmlBundle() throws CmsException {
  
          CmsFile file = m_cms.readFile(m_resource);
          m_bundleFiles.put(null, m_resource);
          m_xmlBundle = CmsXmlContentFactory.unmarshal(m_cms, file);
          initKeySetForXmlBundle();
  
      }
docs: Unmarshals the XML content and adds the file to the bundle files.
  @throws CmsException thrown if reading the file or unmarshaling fails.