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>
    <allfileusages gafcontinue="CO-Lotus_Narn.jpg" />
  </query-continue>
  <query>
    <pages>
      <page ns="6" title="File:Blank.png" missing="" />
      <page ns="6" title="File:CO-Lotus Bart.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Cassie.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Colette.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Jacket.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Lindy.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Lung.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Mai.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Maya.jpg" missing="" />
      <page ns="6" title="File:CO-Lotus Miya.jpg" missing="" />
    </pages>
  </query>
</api>