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>
    <pages>
      <page pageid="61793" ns="0" title="Pseudorthonychiidae" />
      <page pageid="426191" ns="0" title="Huodendron" />
      <page pageid="115008" ns="0" title="Hieracium umbellatum">
        <images>
          <im ns="6" title="File:Commons-logo.svg" />
          <im ns="6" title="File:Illustration Hieracium umbellatum0.jpg" />
        </images>
      </page>
      <page pageid="499013" ns="0" title="Sitona lineatus">
        <images>
          <im ns="6" title="File:Pea Weevil (Sitona lineatus).jpg" />
        </images>
      </page>
      <page pageid="443712" ns="0" title="Lebia fumata" />
      <page pageid="642260" ns="0" title="Streptocarpus × dyeri" />
      <page pageid="436759" ns="0" title="Agrilus cascelius" />
      <page pageid="269298" ns="0" title="Placospherastra" />
      <page pageid="657655" ns="0" title="Carterocephalus palaemon palaemon" />
      <page pageid="295800" ns="0" title="Shewanella frigidimarina" />
    </pages>
  </query>
</api>