docs: protected void validateAppinfoElement(Element appinfoElement) throws CmsXmlException {
  
          // create a document to validate
          Document doc = DocumentHelper.createDocument();
          Element root = doc.addElement(APPINFO_APPINFO);
          // attach the default appinfo schema
          root.add(I_CmsXmlSchemaType.XSI_NAMESPACE);
          root.addAttribute(I_CmsXmlSchemaType.XSI_NAMESPACE_ATTRIBUTE_NO_SCHEMA_LOCATION, APPINFO_SCHEMA_SYSTEM_ID);
          // append the content from the appinfo node in the content definition
          root.appendContent(appinfoElement);
          // now validate the document with the default appinfo schema
          CmsXmlUtils.validateXmlStructure(doc, CmsEncoder.ENCODING_UTF_8, new CmsXmlEntityResolver(null));
      }