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>
    <allpages apcontinue="Banish_the_Darkness" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="1475" ns="0" title="BSOD" />
      <p pageid="1645" ns="0" title="Back Alley Banter" />
      <p pageid="2360" ns="0" title="Back to China" />
      <p pageid="2773" ns="0" title="Back to the Drawing Board" />
      <p pageid="1207" ns="0" title="Bad Advice" />
      <p pageid="2815" ns="0" title="Bad Decisions And Bad News" />
      <p pageid="2175" ns="0" title="Bad Idea, Worse Idea" />
      <p pageid="359" ns="0" title="Baigan" />
      <p pageid="840" ns="0" title="Balancing The Equation" />
      <p pageid="1501" ns="0" title="Bandit King Takes No Arrows To The Knee" />
    </allpages>
  </query>
</api>