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="Thumb|1286" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1282" ns="0" title="Troubleshooting" />
      <page pageid="1283" ns="0" title="Hacking Linux for chumby" />
      <page pageid="1286" ns="0" title="Chumby tricks" />
      <page pageid="1293" ns="0" title="Python" />
      <page pageid="1335" ns="0" title="GNU Toolchain" />
      <page pageid="1399" ns="0" title="Scratchbox" />
      <page pageid="1444" ns="0" title="Chumby hacker board beta" />
      <page pageid="1459" ns="0" title="Building OpenEmbedded (Beta)" />
      <page pageid="1487" ns="0" title="Advanced OpenEmbedded" />
    </pages>
  </query>
</api>