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="SEO_Australia_5035.jpg" />
  </query-continue>
  <query>
    <pages>
      <page ns="6" title="File:Certification 1522.jpg" missing="" />
      <page ns="6" title="File:Certification 3776.jpg" missing="" />
      <page ns="6" title="File:Drop Shipping Companies, Drop Ship Companies 2353.jpg" missing="" />
      <page ns="6" title="File:Hvac install 4561.jpg" missing="" />
      <page ns="6" title="File:Insurance 1891.jpg" missing="" />
      <page ns="6" title="File:Insurance 2587.jpg" missing="" />
      <page ns="6" title="File:Insurance 2604.jpg" missing="" />
      <page ns="6" title="File:Insurance 3153.jpg" missing="" />
      <page ns="6" title="File:Insurance 3710.jpg" missing="" />
      <page ns="6" title="File:PearStory EXMARaLDA.xml" missing="" />
    </pages>
  </query>
</api>