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 atcontinue="Finnish_games_for_download" />
  </query-continue>
  <query>
    <alltransclusions>
      <t ns="10" title="Template:Column-width" />
      <t ns="10" title="Template:Damage series" />
      <t ns="10" title="Template:Featured Finnish games" />
      <t ns="10" title="Template:File Link" />
      <t ns="10" title="Template:Finnish Snake variants for download" />
      <t ns="10" title="Template:Finnish Worms clones" />
      <t ns="10" title="Template:Finnish accident simulators for download" />
      <t ns="10" title="Template:Finnish card games" />
      <t ns="10" title="Template:Finnish cave flying games for download" />
      <t ns="10" title="Template:Finnish city-building games for download" />
    </alltransclusions>
  </query>
</api>