You are seeing a trivial XML (XHTML, actually) document from MT's own site -- replace 'http://www.markup.co.uk:8888/yourxml.xml' in the URL you're fetching with a full URL (http: or https:) for the page you want to see and try again.
The pipeline you ran this through to get here (showcase/id) is a trivial 'do-nothing' pipeline, useful only to check that the pipeline server can actually fetch and parse your XML document successfully, but you can see the pipeline description which was compiled to produce it if you want to.