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>
    <alltransclusions gatcontinue="Current|1825" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1" ns="0" title="Main Page" />
      <page pageid="1508" ns="0" title="Surveillance Cameras" />
      <page pageid="1733" ns="12" title="Help:Contents" />
      <page pageid="2389" ns="2" title="User:Lozzo/Sandbox2" />
      <page pageid="3845" ns="2" title="User:Itsmeok" />
      <page pageid="4522" ns="0" title="Main Page with user videos" />
      <page pageid="4581" ns="0" title="Main Page new icons" />
      <page pageid="4600" ns="0" title="Main Page old icons" />
      <page pageid="5256" ns="0" title="Draft Main Page" />
      <page pageid="5318" ns="0" title="Installing 0710" />
    </pages>
  </query>
</api>