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="Boadicea_Class_Cruiser_(1908)" />
  </query-continue>
  <query>
    <pages>
      <page pageid="3992" ns="0" title="Barr and Stroud" />
      <page pageid="5749" ns="0" title="Barr and Stroud Rangefinders" />
      <page pageid="4744" ns="0" title="Battle Cruiser Force" />
      <page pageid="4032" ns="0" title="Battle of Heligoland Bight" />
      <page pageid="2166" ns="0" title="Battle of the Falkland Islands" />
      <page pageid="3871" ns="0" title="Battlecruiser" />
      <page pageid="5563" ns="0" title="Beagle Class Destroyer (1909)" />
      <page pageid="26138" ns="0" title="Beaufort Testimonial" />
      <page pageid="26257" ns="0" title="Belfast" />
      <page pageid="26250" ns="0" title="Berehaven" />
    </pages>
  </query>
</api>