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="Option_Editeur|1771" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1726" ns="0" title="APP/APG v2.0 Groups View" />
      <page pageid="1741" ns="0" title="Lastest Beta" />
      <page pageid="1773" ns="0" title="APP/APG v2.0 Geometry Editing" />
      <page pageid="1798" ns="0" title="APP/APG v2.0 Render Settings" />
      <page pageid="1845" ns="0" title="Interpolation and blenders" />
      <page pageid="1859" ns="0" title="APP/APG v2.0 Application Settings" />
      <page pageid="2412" ns="10" title="Template:Lien sur image" />
      <page pageid="2413" ns="10" title="Template:Clic" />
    </pages>
  </query>
</api>