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>
    <allfileusages>
      <f fromid="5084" ns="6" title="File:Http://activerain.com/image store/uploads/7/5/2/4/7/ar125177705874257.jpg" />
      <f fromid="4224" ns="6" title="File:Http://farm8.staticflickr.com/7164/6836617263 6eb5af2b96 z.jpg" />
      <f fromid="4224" ns="6" title="File:Http://farm9.staticflickr.com/8284/7548036902 9947c2f7ce z.jpg" />
      <f fromid="4334" ns="6" title="File:Http://pics.freemmorpglist.com/screensmall/foto magic world online.jpg" />
      <f fromid="4897" ns="6" title="File:Http://researched-reviews.com/wp-content/uploads/2012/10/fitbit-5.jpg" />
      <f fromid="5074" ns="6" title="File:Http://www.bionatur.si/wp-content/uploads/2012/03/ThetaHealing-SG-300x251.jpg" />
      <f fromid="5064" ns="6" title="File:Http://www.modernmom.com/sites/default/files/media/articles/152709.jpg" />
      <f fromid="5040" ns="6" title="File:Http://www.vestrainet.com/gallery/portfolio/web-design/web-design-in-toronto-0749.jpg" />
      <f fromid="938" ns="6" title="File:RAW WAR.gif" />
      <f fromid="1" ns="6" title="File:Show image.jpg" />
    </allfileusages>
  </query>
</api>