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>
    <alltransclusions gatcontinue="Cc-by-sa-3.0|836" />
  </query-continue>
  <query>
    <pages>
      <page pageid="226" ns="6" title="File:Introductory Session.pptx" />
      <page pageid="238" ns="6" title="File:NFV vSwitch Requirements.pptx" />
      <page pageid="239" ns="6" title="File:SDN Controller Orchestration.pptx" />
      <page pageid="240" ns="6" title="File:Data Acceleration.pptx" />
      <page pageid="241" ns="6" title="File:Service Assurance.pptx" />
      <page pageid="242" ns="6" title="File:Roadmap Feedback Discussion.pptx" />
      <page pageid="412" ns="6" title="File:TLDK - Network Sample Code - TCP plan.pptx" />
      <page pageid="512" ns="6" title="File:Fd.io vpp overview 29.03.17.pptx" />
      <page pageid="599" ns="6" title="File:Performance Consideration for packet processing.pptx" />
      <page pageid="795" ns="6" title="File:LFN Internships Image.png" />
    </pages>
  </query>
</api>