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>
    <alltransclusions gatcontinue="Right|87" />
  </query-continue>
  <query>
    <pages>
      <page pageid="27" ns="0" title="Roadmap" />
      <page pageid="48" ns="0" title="Hacking:Porting filters to GEGL" />
      <page pageid="87" ns="0" title="Glossary" />
      <page pageid="113" ns="0" title="Hacking:GIMPCon 2003, Berlin, Germany, 2003" />
      <page pageid="141" ns="0" title="Hacking:Porting file plugins to GEGL and GIO" />
      <page pageid="155" ns="0" title="Release:Misc" />
      <page pageid="164" ns="0" title="Hacking:Porting filters to GEGL/UI review" />
    </pages>
  </query>
</api>