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="Beta_carbon_nitride" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="1587" ns="0" title="Back-pressure track segments" />
      <p pageid="808" ns="0" title="Backup plan" />
      <p pageid="1828" ns="0" title="Base Truss Crawler" />
      <p pageid="773" ns="0" title="Base material" />
      <p pageid="1223" ns="0" title="Base material with high potential" />
      <p pageid="881" ns="0" title="Base materials with high potential" />
      <p pageid="1580" ns="0" title="Batch transport for reduction of friction losses" />
      <p pageid="1265" ns="0" title="Beautiful differentiation (Conal Elliott)" />
      <p pageid="1768" ns="0" title="Beryl" />
      <p pageid="503" ns="0" title="Beryllium" />
    </allpages>
  </query>
</api>