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>
    <alllinks galcontinue="Can_I_use_third_party_repositories?|471" />
  </query-continue>
  <query>
    <pages>
      <page pageid="60" ns="0" title="Developer:slkbuild" />
      <page pageid="69" ns="0" title="Submitting packages for inclusion in the Salix repository" />
      <page pageid="70" ns="0" title="Packaging rules" />
      <page pageid="74" ns="0" title="SLKBUILD" />
      <page pageid="398" ns="0" title="LILO bootloader - fix, configure and customize" />
      <page pageid="484" ns="0" title="Can I use third party repositories?" />
      <page pageid="486" ns="0" title="Boot into existing installation" />
      <page pageid="543" ns="0" title="FAQ" />
      <page pageid="748" ns="0" title="Slkbuild" />
      <page pageid="813" ns="0" title="Использование скриптов SlackBuild и SLKBUILD" />
    </pages>
  </query>
</api>