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>
    <allfileusages gafcontinue="Guion.jpg|40" />
  </query-continue>
  <query>
    <pages>
      <page pageid="13" ns="0" title="Cine 64" />
      <page pageid="15" ns="0" title="Cine argentino" />
      <page pageid="22" ns="0" title="Cine universal" />
      <page pageid="23" ns="0" title="Cinecrítica" />
      <page pageid="24" ns="0" title="Cinecuadernos del sur" />
      <page pageid="25" ns="0" title="Cinegraf" />
      <page pageid="26" ns="0" title="Cinema chat" />
      <page pageid="33" ns="0" title="Estrellas" />
      <page pageid="107" ns="0" title="Cine y medios" />
    </pages>
  </query>
</api>