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="254" ns="0" title="Buyer&#039;s Guide" />
      <page pageid="261" ns="0" title="Contensive Developer Add-ons" />
      <page pageid="1" ns="0" title="Contensive Documentation" />
      <page pageid="226" ns="0" title="Contensive Library Architecture" />
      <page pageid="33" ns="0" title="Contensive Public Add-ons" />
      <page pageid="305" ns="0" title="Managing AWS SES (Simple Email Service)" />
      <page pageid="208" ns="0" title="TCA 2015 New Site Features" />
    </pages>
  </query>
</api>