GN4 texts are stored internally using an XML format called "t markup" that encodes the 'legacy' GNML markup tags. The namespace is http://www.teradp.com/schemas/GN3/t.xsd and it is usually mapped to a prefix 't'.

This markup can be converted to HTML for Web publishing through a built-in convertMarkup conversion function, you can call for any XSL transformation executed by the server - either via workflows or by a '../do.ashx?cmd=feed' command or by XML export commands.

See

convertMarkup XSLT extension