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>
    <allimages gaicontinue="Appointments_pic2.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1585" ns="6" title="File:Acl new.png" />
      <page pageid="1586" ns="6" title="File:Acl show.png" />
      <page pageid="1682" ns="6" title="File:Address group show.png" />
      <page pageid="643" ns="6" title="File:Address pic1.png" />
      <page pageid="644" ns="6" title="File:Address pic2.png" />
      <page pageid="645" ns="6" title="File:Address pic3.png" />
      <page pageid="649" ns="6" title="File:Appointments pic1.png" />
      <page pageid="658" ns="6" title="File:Appointments pic10.png" />
      <page pageid="659" ns="6" title="File:Appointments pic11.png" />
      <page pageid="660" ns="6" title="File:Appointments pic12.png" />
    </pages>
  </query>
</api>