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="Cataloginfo.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="68" ns="6" title="File:Account.png" />
      <page pageid="84" ns="6" title="File:Advanced options.png" />
      <page pageid="5" ns="6" title="File:Align combine menu.png" />
      <page pageid="14" ns="6" title="File:Align stacked frames1.png" />
      <page pageid="15" ns="6" title="File:Align stacked frames2.png" />
      <page pageid="16" ns="6" title="File:Align stacked frames3.jpg" />
      <page pageid="17" ns="6" title="File:Align stacked frames4.jpg" />
      <page pageid="69" ns="6" title="File:Allsky.png" />
      <page pageid="91" ns="6" title="File:BennettF214.png" />
      <page pageid="88" ns="6" title="File:Booked.png" />
    </pages>
  </query>
</api>