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="Note|349" />
  </query-continue>
  <query>
    <pages>
      <page pageid="10" ns="12" title="Help:Editing" />
      <page pageid="12" ns="0" title="Check Engine Light (CEL)" />
      <page pageid="22" ns="0" title="Coolant Pump" />
      <page pageid="183" ns="0" title="Cambelt-change" />
      <page pageid="214" ns="0" title="Lights rear" />
      <page pageid="263" ns="0" title="Gearshift cable replacement" />
      <page pageid="308" ns="0" title="Water Pump" />
    </pages>
  </query>
</api>