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>
    <allimages gaicontinue="Pass_protect.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4" ns="6" title="File:Access webmail.png" />
      <page pageid="16" ns="6" title="File:Account manager.png" />
      <page pageid="3" ns="6" title="File:Add email.png" />
      <page pageid="6" ns="6" title="File:Add ftp.png" />
      <page pageid="17" ns="6" title="File:Domain manager.png" />
      <page pageid="14" ns="6" title="File:Email forwards.png" />
      <page pageid="36" ns="6" title="File:File perms.png" />
      <page pageid="25" ns="6" title="File:Hosting manager.png" />
      <page pageid="10" ns="6" title="File:Nameservers.jpeg">
        <duplicatefiles>
          <df name="Nameservers.jpg" user="Lamphost" timestamp="2013-07-19T21:39:59Z" />
        </duplicatefiles>
      </page>
      <page pageid="12" ns="6" title="File:Nameservers.jpg">
        <duplicatefiles>
          <df name="Nameservers.jpeg" user="Lamphost" timestamp="2013-07-19T21:36:56Z" />
        </duplicatefiles>
      </page>
    </pages>
  </query>
</api>