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>
    <alllinks galcontinue="Lost_Password" />
  </query-continue>
  <query>
    <pages>
      <page ns="0" title="FileZilla" missing="" />
      <page pageid="33" ns="0" title="Common Billing Questions" />
      <page pageid="7" ns="0" title="Control Panel" />
      <page pageid="23" ns="0" title="Current Software Versions" />
      <page pageid="11" ns="0" title="DNS" />
      <page pageid="26" ns="0" title="Domain Name Registration" />
      <page pageid="2" ns="0" title="Email" />
      <page pageid="5" ns="0" title="FTP" />
      <page pageid="35" ns="0" title="File Permissions" />
      <page pageid="1" ns="0" title="LAMP Host Knowledge Base" />
    </pages>
  </query>
</api>