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>
    <alltransclusions gatcontinue="Icode|12" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4" ns="0" title="Symbian OS Platform Security/02. Platform Security Concepts" />
      <page pageid="5" ns="0" title="Symbian OS Platform Security/03. The Platform Security Environment" />
      <page pageid="6" ns="0" title="Symbian OS Platform Security/04. How to Write Secure Applications" />
      <page pageid="7" ns="0" title="Symbian OS Platform Security/05. How to Write Secure Servers" />
      <page pageid="8" ns="0" title="Symbian OS Platform Security/06. How to Write Secure Plug-ins" />
      <page pageid="9" ns="0" title="Symbian OS Platform Security/07. Sharing Data Safely" />
      <page pageid="10" ns="0" title="Symbian OS Platform Security/08. Native Software Installer" />
      <page pageid="11" ns="0" title="Symbian OS Platform Security/09. Enabling Platform Security" />
      <page pageid="171" ns="0" title="Enigma/Sample Messages" />
    </pages>
  </query>
</api>