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>
    <allpages apcontinue="Comprehensive_Index" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="231" ns="0" title="Behavioral Economics" />
      <p pageid="142" ns="0" title="Best Practices for Data Protection and Privacy" />
      <p pageid="108" ns="0" title="Beyond Fear" />
      <p pageid="262" ns="0" title="Book" />
      <p pageid="50" ns="0" title="Books" />
      <p pageid="221" ns="0" title="Broad Topics" />
      <p pageid="268" ns="0" title="Case Studies" />
      <p pageid="219" ns="0" title="Cloud Computing" />
      <p pageid="23" ns="0" title="Combatant Status and Computer Network Attack" />
      <p pageid="212" ns="0" title="Communications" />
    </allpages>
  </query>
</api>