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="BE109_Fall10_Mod1_Day2_Michelle.pdf" />
  </query-continue>
  <query>
    <allfileusages>
      <f ns="6" title="File:B003246h.pdf" />
      <f ns="6" title="File:BA1.jpg" />
      <f ns="6" title="File:BATTERIES20.1092019.pdf" />
      <f ns="6" title="File:BATTERIES 20.109 2018.pdf" />
      <f ns="6" title="File:BATTERIES 20.109 Fall 2017.pdf" />
      <f ns="6" title="File:BE109 Fall09 Mod1 Day2 Lecture Engelward TO POST.pdf" />
      <f ns="6" title="File:BE109 Fall09 Mod1 Day3 Lecture To Post.pdf" />
      <f ns="6" title="File:BE109 Fall09 Mod1 Day6 to POST.pdf" />
      <f ns="6" title="File:BE109 Fall09 Mod1 Day7 to POST.pdf" />
      <f ns="6" title="File:BE109 Fall09 Mod1 Day8 to POST.pdf" />
    </allfileusages>
  </query>
</api>