You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
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<?xml version="1.0"?>
<api>
  <query>
    <blocks>
      <block id="1" user="Keithmorris0910" by="Illyanadmc" timestamp="2010-01-11T13:56:39Z" expiry="infinity" reason="Spamming links to external sites" nocreate="" autoblock="" allowusertalk="" />
    </blocks>
  </query>
</api>