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="Env1.png" />
  </query-continue>
  <query>
    <allfileusages>
      <f ns="6" title="File:BST example.png" />
      <f ns="6" title="File:Balanced vs unbalanced BST.png" />
      <f ns="6" title="File:Binary tree.png" />
      <f ns="6" title="File:Cars.jpg" />
      <f ns="6" title="File:Casinovietqq188 song bai truc tuyen casino online uy tin hang dau Viet Nam.jpg" />
      <f ns="6" title="File:Compound statement.png" />
      <f ns="6" title="File:Cs61a.png" />
      <f ns="6" title="File:Decision tree.png" />
      <f ns="6" title="File:Deep list.png" />
      <f ns="6" title="File:Down Arrow Icon.png" />
    </allfileusages>
  </query>
</api>