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="Feed-icon.png" />
  </query-continue>
  <query>
    <pages>
      <page ns="6" title="File:Burka on the job - Crossing guard in Alberta.jpg" missing="" />
      <page ns="6" title="File:Cloud icon.jpg" missing="" />
      <page ns="6" title="File:Commons-logo.svg" missing="" />
      <page ns="6" title="File:Communism - Nazism - Feminism.svg" missing="" />
      <page ns="6" title="File:Der dressierte Mann.jpg" missing="" />
      <page ns="6" title="File:Der dressierte Mann (Die Trilogie).jpg" missing="" />
      <page ns="6" title="File:Die 25-Stunden-Woche.jpg" missing="" />
      <page ns="6" title="File:Disambig-dark.png" missing="" />
      <page ns="6" title="File:Esther Vilar 1975.jpg" missing="" />
      <page ns="6" title="File:Esther Vilar 2005.jpg" missing="" />
    </pages>
  </query>
</api>