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>
    <pages>
      <page pageid="36" ns="0" title="Creating Digital Delivery Licensing Module" />
      <page pageid="95" ns="0" title="Add a Top X Sales by State pie chart to your Dashboard" />
      <page pageid="97" ns="0" title="How to write Contact Us Control" />
      <page pageid="113" ns="12" title="Help:Wikitext examples" />
    </pages>
  </query>
</api>