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>
    <allredirects garcontinue="Barrow_arrows" />
  </query-continue>
  <query>
    <pages>
      <page pageid="6200" ns="0" title="Baby Blue Dragon" />
      <page pageid="4970" ns="0" title="Baby corporeal beast" />
      <page pageid="3858" ns="0" title="Baby dragons" />
      <page pageid="757" ns="0" title="Bandos armour" />
      <page pageid="6746" ns="0" title="Bandos godblade" />
      <page pageid="623" ns="0" title="Bandos godsword" />
      <page pageid="8471" ns="0" title="Bane ore" />
      <page pageid="2964" ns="0" title="Barb bolt tips" />
      <page pageid="971" ns="0" title="Barbarian" />
      <page pageid="28" ns="0" title="Barbarian Assistance" />
    </pages>
  </query>
</api>