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="Neckerchief.png|8" />
  </query-continue>
  <query>
    <allfileusages>
      <f ns="6" title="File:Cabrosha mug web.jpg" />
      <f ns="6" title="File:Cabrosha mug web.jpg" />
      <f ns="6" title="File:Emb.png" />
      <f ns="6" title="File:Emb.png" />
      <f ns="6" title="File:Felt orca.jpeg" />
      <f ns="6" title="File:Felt orca.jpeg" />
      <f ns="6" title="File:First chenille.jpeg" />
      <f ns="6" title="File:NOAC 2015 cont.jpg" />
      <f ns="6" title="File:NOAC 2015 fund.jpg" />
      <f ns="6" title="File:NOAC 2015 fund mylar.jpg" />
    </allfileusages>
  </query>
</api>