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>
    <allredirects garcontinue="Bromure_de_sodium" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2206" ns="0" title="Ballon" />
      <page pageid="2209" ns="0" title="Benzaldéhyde" />
      <page pageid="389" ns="0" title="Bisacrylamide" />
      <page pageid="2152" ns="0" title="Bleu de bromothymol" />
      <page pageid="642" ns="0" title="Bleu de méthylène" />
      <page pageid="1739" ns="0" title="Borate de méthyle" />
      <page pageid="1522" ns="0" title="Bouillottes magiques" />
      <page pageid="825" ns="0" title="Bromate de potassium" />
      <page pageid="775" ns="0" title="Bromate de sodium" />
      <page pageid="1580" ns="0" title="Bromure de potassium" />
    </pages>
  </query>
</api>