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>
    <allpages gapcontinue="Tricks-and-tips" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1789" ns="0" title="Test de la solution base de données" contentmodel="wikitext" pagelanguage="en" touched="2006-06-07T15:03:08Z" lastrevid="5313" counter="" length="2754" />
      <page pageid="1788" ns="0" title="Test de la solution fichier XML" contentmodel="wikitext" pagelanguage="en" touched="2006-06-07T14:22:02Z" lastrevid="5312" counter="" length="3898" />
      <page pageid="1787" ns="0" title="Test de la solution fichier texte" contentmodel="wikitext" pagelanguage="en" touched="2006-06-07T13:47:29Z" lastrevid="5310" counter="" length="1566" />
      <page pageid="948" ns="0" title="Time unit" contentmodel="wikitext" pagelanguage="en" touched="2009-08-04T09:59:05Z" lastrevid="6845" counter="" length="3019" />
    </pages>
  </query>
</api>