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 afcontinue="EDGE-experience.png|500" />
  </query-continue>
  <query>
    <allfileusages>
      <f ns="6" title="File:Bailouts.jpg" />
      <f ns="6" title="File:Bankers.jpg" />
      <f ns="6" title="File:Barn raising depiction.jpg" />
      <f ns="6" title="File:BrokenLink.png" />
      <f ns="6" title="File:Buffalo Sisters Gift Circle March 2010.jpg" />
      <f ns="6" title="File:Capitalist mentality.jpg" />
      <f ns="6" title="File:Casa Robino.jpg" />
      <f ns="6" title="File:Connahs Quay 1992.jpg" />
      <f ns="6" title="File:Demonetization.jpg" />
      <f ns="6" title="File:Donate.gif" />
    </allfileusages>
  </query>
</api>