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="DMS_OH_O2.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1274" ns="6" title="File:BNU LAI 2010.png" />
      <page pageid="1122" ns="6" title="File:Boxes removed from EMEP mask.png" />
      <page pageid="454" ns="6" title="File:C2H6 0-8km TAO&amp;GC 2006.pdf" />
      <page pageid="404" ns="6" title="File:C2H6 OH.png" />
      <page pageid="915" ns="6" title="File:CONV H2O2.png" />
      <page pageid="766" ns="6" title="File:Cherry pick 1.jpg" />
      <page pageid="767" ns="6" title="File:Cherry pick 2.jpg" />
      <page pageid="768" ns="6" title="File:Cherry pick 3.jpg" />
      <page pageid="410" ns="6" title="File:DMS NO3.png" />
      <page pageid="409" ns="6" title="File:DMS OH.png" />
    </pages>
  </query>
</api>