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="CMOS_e_OpenCollector_schemi.png|913" />
  </query-continue>
  <query>
    <allfileusages>
      <f ns="6" title="File:BCP example 01.png" />
      <f ns="6" title="File:BCP example 02.png" />
      <f ns="6" title="File:BCP example 03.png" />
      <f ns="6" title="File:BCP help usage.png" />
      <f ns="6" title="File:CLR Assembly 01.png" />
      <f ns="6" title="File:CLR Assembly 03.png" />
      <f ns="6" title="File:CLR Assembly 04.png" />
      <f ns="6" title="File:CLR Assembly 05.png" />
      <f ns="6" title="File:CLR Assembly 06.png" />
      <f ns="6" title="File:CLR Assembly 07.png" />
    </allfileusages>
  </query>
</api>