You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allfileusages gafcontinue="Catamaran-close-hauled.png|1707" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1413" ns="0" title="Nevermore Systems Descriptions" />
      <page pageid="1720" ns="0" title="Ratings" />
      <page pageid="1800" ns="0" title="X-Dimension systems" />
      <page pageid="1810" ns="0" title="X-Dimension vessel documentation" />
      <page pageid="1883" ns="0" title="X Dimension Event History" />
      <page pageid="2058" ns="0" title="Mashnee vessel documentation" />
    </pages>
  </query>
</api>