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>
    <links gplcontinue="1|0|Primauteur" />
  </query-continue>
  <query>
    <pages>
      <page ns="0" title="-" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="Administrativia" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="Annuaire du PLUS" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="Blik" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="Blog" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="Etat des travaux" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="FAQ" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="Introduction" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page ns="0" title="Liens et Questions" missing="" contentmodel="wikitext" pagelanguage="en" />
      <page pageid="6" ns="0" title="Plex" contentmodel="wikitext" pagelanguage="en" touched="2016-12-14T18:44:29Z" lastrevid="10" counter="3879" length="708" new="" />
    </pages>
  </query>
</api>