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>
    <allredirects garcontinue="Urchin" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1311" ns="0" title="Email Accounts" />
      <page pageid="1313" ns="0" title="Email Aliases" />
      <page pageid="1319" ns="0" title="Email Failed Addresses" />
      <page pageid="1318" ns="0" title="Email Groups" />
      <page pageid="1557" ns="0" title="Export DNS Info" />
      <page pageid="1325" ns="0" title="Greylisting" />
      <page pageid="1467" ns="0" title="IPv6" />
      <page pageid="1354" ns="0" title="Microsoft Entourage 2004" />
      <page pageid="1327" ns="0" title="SupraNet Mailguard" />
      <page pageid="1" ns="0" title="SupraNet Technical Support" />
    </pages>
  </query>
</api>