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>
    <allpages>
      <p pageid="5322" ns="0" title="Baptismal Records, Children of Henrich Dittman" />
      <p pageid="6387" ns="0" title="Barbara A. (Unknown)" />
      <p pageid="1764" ns="0" title="Barbara Ann Hartman" />
      <p pageid="4746" ns="0" title="Barbara Lucas Van Kessel" />
      <p pageid="1525" ns="0" title="Barbara Paden" />
      <p pageid="4702" ns="0" title="Barbara Philistia Kline" />
      <p pageid="2481" ns="0" title="Barbara Walter" />
      <p pageid="3817" ns="0" title="Barber County Index, Obituary of Jennie Osborn" />
      <p pageid="3997" ns="0" title="Barnard V. Stoughton" />
      <p pageid="3776" ns="0" title="Barnard VanZant Stoughton" />
    </allpages>
  </query>
  <query-continue>
    <allpages apcontinue="Baum_Surname" />
  </query-continue>
</api>