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>
    <allimages gaicontinue="13120429-FBI-Summary-about-Alleged-Flight-175-Hijacker-Hamza-Alghamdi.pdf" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1320" ns="6" title="File:0822-met-WTC large.jpg" />
      <page pageid="1425" ns="6" title="File:08Jun Donaldson.pdf" />
      <page pageid="1426" ns="6" title="File:08Sep Socias.pdf" />
      <page pageid="518" ns="6" title="File:091101Pentagon planepiece.jpg" />
      <page pageid="1318" ns="6" title="File:13-DPP.pdf" />
      <page pageid="1679" ns="6" title="File:13120295-FBI-Summary-about-Alleged-United-93-Hijacker-Ahmed-Alnami.pdf" />
      <page pageid="1680" ns="6" title="File:13120301-FBI-Summary-about-Alleged-United-175-Hijacker-Ahmed-Alghamdi.pdf" />
      <page pageid="1681" ns="6" title="File:13120308-FBI-Summary-about-Alleged-United-93-Hijacker-Ahmed-AlHaznawi.pdf" />
      <page pageid="1682" ns="6" title="File:13120363-FBI-Summary-about-Alleged-Flight-175-Hijacker-Fayez-Ahmed-Banihammad.pdf" />
      <page pageid="1683" ns="6" title="File:13120414--FBI-Summary-about-Alleged-Flight-77-Hijacker-Hani-Hanjour.pdf">
        <duplicatefiles>
          <df name="PENTTBOM_About_Hanjour.pdf" user="Mike" timestamp="2009-04-24T09:02:00Z" />
        </duplicatefiles>
      </page>
    </pages>
  </query>
</api>