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="Conformal_latitude" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="31" ns="0" title="Balance of errors" />
      <p pageid="32" ns="0" title="Belt" />
      <p pageid="33" ns="0" title="Case of a map projection" />
      <p pageid="34" ns="0" title="Central meridian" />
      <p pageid="35" ns="0" title="Central projections" />
      <p pageid="36" ns="0" title="Colatitude" />
      <p pageid="37" ns="0" title="Combined projections" />
      <p pageid="38" ns="0" title="Composite projections" />
      <p pageid="39" ns="0" title="Compression" />
      <p pageid="40" ns="0" title="Condensed projections" />
    </allpages>
  </query>
</api>