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="Anthrotut_starting.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1934" ns="6" title="File:2007 Halloween Party.png" />
      <page pageid="1435" ns="6" title="File:Anthrotut LegsInvisiprimStretch.jpg" />
      <page pageid="1430" ns="6" title="File:Anthrotut change headsize.jpg" />
      <page pageid="1428" ns="6" title="File:Anthrotut crushed.jpg" />
      <page pageid="1438" ns="6" title="File:Anthrotut end.jpg" />
      <page pageid="1439" ns="6" title="File:Anthrotut finished anthro options.jpg" />
      <page pageid="1436" ns="6" title="File:Anthrotut grabbodytatoo.jpg" />
      <page pageid="1427" ns="6" title="File:Anthrotut hatchlingparts.jpg" />
      <page pageid="1429" ns="6" title="File:Anthrotut head contents.jpg" />
      <page pageid="1437" ns="6" title="File:Anthrotut selectBodyTatoo.jpg" />
    </pages>
  </query>
</api>