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>
    <pages>
      <page pageid="8346" ns="0" title="Breakthough to Sustainable mind" />
      <page pageid="8347" ns="0" title="Breakthough to the Sustainable Business" />
      <page pageid="8348" ns="0" title="Breakthough to Sustainable Management" />
      <page pageid="8486" ns="0" title="技術革新と社会の変化が創り出す新たなニーズに向けて事業を興す-1" />
    </pages>
  </query>
</api>