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>
    <general mainpage="Accueil" base="http://cath.info/index.php/Accueil" sitename="Cath.Info" logo="http://cath.info/images/wikilogo.gif" generator="MediaWiki 1.23.3" phpversion="5.5.38" phpsapi="fpm-fcgi" dbtype="sqlite" dbversion="3.7.17" imagewhitelistenabled="" langconversion="" titleconversion="" linkprefixcharset="" linkprefix="" linktrail="/^([a-zàâçéèêîôûäëïöüùÇÉÂÊÎÔÛÄËÏÖÜÀÈÙ]+)(.*)$/sDu" case="first-letter" lang="fr" fallback8bitEncoding="windows-1252" writeapi="" timezone="UTC" timeoffset="0" articlepath="/index.php/$1" scriptpath="" script="/index.php" server="http://cath.info" wikiid="my_wiki" time="2024-04-27T09:49:16Z" maxuploadsize="104857600" favicon="http://cath.info/favicon.ico">
      <fallback>
        <lang code="en" />
      </fallback>
      <thumblimits>
        <limit>120</limit>
        <limit>150</limit>
        <limit>180</limit>
        <limit>200</limit>
        <limit>250</limit>
        <limit>300</limit>
      </thumblimits>
      <imagelimits>
        <limit width="320" height="240" />
        <limit width="640" height="480" />
        <limit width="800" height="600" />
        <limit width="1024" height="768" />
        <limit width="1280" height="1024" />
      </imagelimits>
    </general>
    <namespaces>
      <ns id="-2" case="first-letter" canonical="Media" xml:space="preserve">Média</ns>
      <ns id="-1" case="first-letter" canonical="Special" xml:space="preserve">Spécial</ns>
      <ns id="0" case="first-letter" content="" xml:space="preserve" />
      <ns id="1" case="first-letter" subpages="" canonical="Talk" xml:space="preserve">Discussion</ns>
      <ns id="2" case="first-letter" subpages="" canonical="User" xml:space="preserve">Utilisateur</ns>
      <ns id="3" case="first-letter" subpages="" canonical="User talk" xml:space="preserve">Discussion utilisateur</ns>
      <ns id="4" case="first-letter" subpages="" canonical="Project" xml:space="preserve">Cath.Info</ns>
      <ns id="5" case="first-letter" subpages="" canonical="Project talk" xml:space="preserve">Discussion Cath.Info</ns>
      <ns id="6" case="first-letter" canonical="File" xml:space="preserve">Fichier</ns>
      <ns id="7" case="first-letter" subpages="" canonical="File talk" xml:space="preserve">Discussion fichier</ns>
      <ns id="8" case="first-letter" subpages="" canonical="MediaWiki" xml:space="preserve">MediaWiki</ns>
      <ns id="9" case="first-letter" subpages="" canonical="MediaWiki talk" xml:space="preserve">Discussion MediaWiki</ns>
      <ns id="10" case="first-letter" canonical="Template" xml:space="preserve">Modèle</ns>
      <ns id="11" case="first-letter" subpages="" canonical="Template talk" xml:space="preserve">Discussion modèle</ns>
      <ns id="12" case="first-letter" subpages="" canonical="Help" xml:space="preserve">Aide</ns>
      <ns id="13" case="first-letter" subpages="" canonical="Help talk" xml:space="preserve">Discussion aide</ns>
      <ns id="14" case="first-letter" canonical="Category" xml:space="preserve">Catégorie</ns>
      <ns id="15" case="first-letter" subpages="" canonical="Category talk" xml:space="preserve">Discussion catégorie</ns>
    </namespaces>
    <namespacealiases>
      <ns id="1" xml:space="preserve">Discuter</ns>
      <ns id="2" xml:space="preserve">Utilisatrice</ns>
      <ns id="3" xml:space="preserve">Discussion Utilisateur</ns>
      <ns id="3" xml:space="preserve">Discussion utilisatrice</ns>
      <ns id="6" xml:space="preserve">Image</ns>
      <ns id="7" xml:space="preserve">Discussion Fichier</ns>
      <ns id="7" xml:space="preserve">Discussion Image</ns>
      <ns id="7" xml:space="preserve">Image talk</ns>
      <ns id="11" xml:space="preserve">Discussion Modèle</ns>
      <ns id="13" xml:space="preserve">Discussion Aide</ns>
      <ns id="15" xml:space="preserve">Discussion Catégorie</ns>
    </namespacealiases>
    <statistics pages="7" articles="2" views="135303" edits="34" images="1" users="1" activeusers="0" admins="1" jobs="0" />
  </query>
</api>