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 apcontinue="Comment_créer_un_serveur_web_Nginx" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="112" ns="0" title="Black and White Notifier" />
      <p pageid="41" ns="0" title="CSSMatch" />
      <p pageid="265" ns="0" title="Comment chrooter les utilisateurs" />
      <p pageid="289" ns="0" title="Comment configurer Exim4 en SmartHost" />
      <p pageid="27" ns="0" title="Comment créer un serveur Mumble" />
      <p pageid="12" ns="0" title="Comment créer un serveur Teamspeak 3" />
      <p pageid="25" ns="0" title="Comment créer un serveur de jeu" />
      <p pageid="49" ns="0" title="Comment créer un serveur ftp" />
      <p pageid="282" ns="0" title="Comment créer un serveur web" />
      <p pageid="16" ns="0" title="Comment créer un serveur web (Apache2)" />
    </allpages>
  </query>
</api>