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>
    <allredirects garcontinue="Installation_of_older_Knoppix_to_HDD|1673" />
  </query-continue>
  <query>
    <pages>
      <page pageid="748" ns="0" title="Basic PoorMans" />
      <page pageid="777" ns="0" title="Customising FAQ" />
      <page pageid="789" ns="0" title="Deutsch Install FAQ" />
      <page pageid="1050" ns="0" title="Cheat CodesDeutsch" />
      <page pageid="1504" ns="0" title="HD Install Warning not to do it" />
      <page pageid="1513" ns="0" title="Cheat code" />
      <page pageid="1594" ns="0" title="Complete list of packages included with Knoppix" />
      <page pageid="1625" ns="2" title="User:Mimes" />
      <page pageid="2087" ns="0" title="Completely new HD based HowTo page" />
      <page pageid="2124" ns="0" title="HD Installation Warnung" />
    </pages>
  </query>
</api>