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="1562" ns="0" title="Disable Windows Firewall from Commandline" />
      <page pageid="1528" ns="0" title="Logon/Startup Scripts" />
      <page pageid="1696" ns="0" title="NIC Bonding on XenServer" />
      <page pageid="1685" ns="0" title="Renew Expired Security Certificate (Exchange 2007)" />
      <page pageid="1731" ns="0" title="RickRoll" />
      <page pageid="1624" ns="0" title="Software Deployment with Group Policy" />
    </pages>
  </query>
</api>