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>
    <pages>
      <page pageid="9" ns="0" title="Club de Golf Fortín Tordillo" />
      <page pageid="220" ns="0" title="Pablo Guglieri" />
      <page pageid="1" ns="0" title="Portada" />
      <page pageid="252" ns="0" title="Quinta Municipal Alejandro Abbiate" />
      <page pageid="250" ns="0" title="Émile Honoré Daireaux" />
    </pages>
  </query>
</api>