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="S&amp;D-Kendal_Multiview_Market.jpg|198" />
  </query-continue>
  <query>
    <allfileusages>
      <f ns="6" title="File:Camms Yard 89 Stricklandgate -An Old Kendal Yard.jpg" />
      <f ns="6" title="File:Dowker&#039;s Hospital Reduced Rules.jpg" />
      <f ns="6" title="File:Dowker&#039;s Hospital Stengal E16342.jpg" />
      <f ns="6" title="File:Finkle Street Old Pump Inn Fish Market JHHogg.png" />
      <f ns="6" title="File:Gillinggate Roods Terrace.jpg" />
      <f ns="6" title="File:Greenside.png" />
      <f ns="6" title="File:James-Kerr-Murray-Ironmonger-Advert-53-Stricklandgate.jpg" />
      <f ns="6" title="File:Kirkland Yard 23 Curwen1900.png" />
      <f ns="6" title="File:Liverpool and Kendal Stage Coach Advert 1768 Kings Arms.jpg" />
      <f ns="6" title="File:Rose and Crown Inn pre1876.jpg" />
    </allfileusages>
  </query>
</api>