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="2328" ns="0" title="Bronson Yung" />
      <page pageid="2437" ns="0" title="CSI Adelaide: Was Trayvon Martin murdered?" />
      <page pageid="1406" ns="0" title="Cipher Cracking 2009" />
      <page pageid="2963" ns="0" title="Cracking the Voynich Code 2015 - Final Report" />
      <page pageid="2436" ns="0" title="Junk" />
    </pages>
  </query>
</api>