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="Barleria_prionitis_(Porcupine_flower)_in_Hyderabad,_AP_W_IMG_9999.jpg|677" />
  </query-continue>
  <query>
    <pages>
      <page pageid="619" ns="0" title="Division:Education" />
      <page pageid="677" ns="0" title="Barleria prionitis" />
      <page pageid="894" ns="0" title="Plants of commercial importance" />
      <page pageid="930" ns="0" title="Aegle marmelos" />
      <page pageid="2269" ns="0" title="Lord Shiva and leaves of Bael" />
      <page pageid="2360" ns="0" title="Bhils of Central India and Parvati&#039;s curse" />
      <page pageid="2386" ns="0" title="Official flora and fauna of India" />
      <page pageid="2423" ns="0" title="Native cow varieties of India" />
    </pages>
  </query>
</api>