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="Cosmo_21-4.jpg|521" />
  </query-continue>
  <query>
    <pages>
      <page pageid="67" ns="0" title="FD3S:Cooling System Diagram" />
      <page pageid="100" ns="2" title="User:DonutBob" />
      <page pageid="155" ns="0" title="1968-1973 Mazda R100 / Familia Rotary" />
      <page pageid="157" ns="0" title="1970-1978 Mazda RX-2 / Capella Rotary" />
      <page pageid="182" ns="0" title="RE:How it Works" />
      <page pageid="496" ns="0" title="1970 Mazda RX-500 Prototype" />
      <page pageid="508" ns="0" title="1970 Mazda Chevron B16" />
      <page pageid="521" ns="0" title="2002 Mazda Cosmo 21 Concept" />
    </pages>
  </query>
</api>