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="Feed-icon.png|1409" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1395" ns="0" title="Probak egiteko gunea" />
      <page pageid="1435" ns="0" title="BubbleShare: argazkiak partekatzeko gune bat" />
      <page pageid="1473" ns="0" title="Ebaluazioaren definizio zabal baterantz" />
      <page pageid="1482" ns="0" title="Didaktika orokorra" />
      <page pageid="1484" ns="0" title="Euskara eta ikas-estiloak" />
      <page pageid="1668" ns="0" title="Ikas-estiloen beste sailkapen batzuk" />
      <page pageid="1686" ns="0" title="Ekoizpena" />
      <page pageid="1710" ns="0" title="Gramatikaren lanketarako markoa" />
    </pages>
  </query>
</api>