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="Flagcanada-mini.gif|7" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2" ns="2" title="User:DavidMRDSpencer" />
      <page pageid="6" ns="14" title="Category:A" />
      <page pageid="52" ns="0" title="Contact our Project Leader" />
      <page pageid="73" ns="0" title="David M.R.D. Spencer" />
      <page pageid="76" ns="0" title="Interview with David Spencer" />
      <page pageid="167" ns="0" title="Jim Leek" />
      <page pageid="210" ns="0" title="Celebration of the Life of Jim Leek" />
      <page pageid="229" ns="0" title="Cam Shillington" />
      <page pageid="241" ns="0" title="Byline" />
    </pages>
  </query>
</api>