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="Boehm.jpg|2691" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2542" ns="0" title="MultiScaleMicroscopy" />
      <page pageid="2544" ns="0" title="MultiScale Microscopy Detailed" />
      <page pageid="2550" ns="0" title="PA 8001 2013 Practical 0" />
      <page pageid="2569" ns="0" title="Industrial Workshop February 2013" />
      <page pageid="2615" ns="0" title="MECHWEED" />
      <page pageid="2744" ns="0" title="Bertil Svensson" />
      <page pageid="4019" ns="0" title="PA 8001 2014 Practical 0" />
      <page pageid="4300" ns="0" title="PA 8001 2015 Practical 0" />
      <page pageid="4529" ns="0" title="HSST 2018" />
    </pages>
  </query>
</api>