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>
    <allfileusages gafcontinue="L2-24_0_1-OPL2-(1B)-07122017.png|3543" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1927" ns="0" title="Managing Templates for OnePager Live (Portal)" />
      <page pageid="3543" ns="0" title="Managing Templates for OnePager Live Beta 2 (Portal)" />
      <page pageid="11646" ns="0" title="Merging the Wrong Tasks into a Chart for Version 7.2 - OnePager Bundle - Oracle Primavera P6" />
      <page pageid="11647" ns="0" title="Merging the Wrong Tasks into a Chart for Version 7.2 - OnePager Bundle - Smartsheet" />
      <page pageid="11656" ns="0" title="Making Multi-Project Charts for Oracle Primavera P6 for Version 7.2" />
      <page pageid="11801" ns="0" title="Template Only Features for Smartsheet Source Plans in OnePager Version 7.2" />
    </pages>
  </query>
</api>