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>
    <alllinks galcontinue="Battles_on_Arena|382" />
  </query-continue>
  <query>
    <pages>
      <page pageid="358" ns="0" title="Main Page" />
      <page pageid="361" ns="0" title="FAQ" />
      <page pageid="370" ns="0" title="Quick start" />
      <page pageid="401" ns="0" title="Battles on Arena" />
      <page pageid="409" ns="0" title="Invitation to battle and team creation" />
      <page pageid="445" ns="0" title="Rating" />
    </pages>
  </query>
</api>