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>
    <allfileusages gafcontinue="Crab.png|75" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4" ns="0" title="Crab Clan" />
      <page pageid="62" ns="0" title="Garanto Province (Crab)" />
      <page pageid="67" ns="0" title="Hida Jotaka" />
      <page pageid="68" ns="0" title="Hida Sorai" />
      <page pageid="70" ns="0" title="Hiruma Yabu" />
      <page pageid="183" ns="0" title="Ichiro Oniji" />
      <page pageid="531" ns="6" title="File:Mon monk.jpg" />
      <page pageid="684" ns="0" title="HoR4: Minor Clans" />
      <page pageid="771" ns="0" title="Monk Player Pages" />
      <page pageid="790" ns="0" title="Becky J." />
    </pages>
  </query>
</api>