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"?>
    <blocks bkstart="2012-02-28T01:22:00Z" />
      <block id="18" user="Tom Miller" by="LordOfBikes" timestamp="2016-06-08T10:01:44Z" expiry="infinity" reason="possibly spam account" nocreate="" />
      <block id="17" user="Tim Andru" by="LordOfBikes" timestamp="2016-06-08T09:59:45Z" expiry="infinity" reason="possibly spam account" nocreate="" />
      <block id="16" user="Roland Taboure" by="LordOfBikes" timestamp="2016-06-02T21:54:50Z" expiry="infinity" reason="Spammer" nocreate="" />
      <block id="15" user="Anjilo Jilo" by="LordOfBikes" timestamp="2016-05-31T18:48:25Z" expiry="infinity" reason="probably spam" nocreate="" />
      <block id="14" user="Sugan Singh" by="LordOfBikes" timestamp="2016-05-31T18:46:18Z" expiry="infinity" reason="probably spam" nocreate="" />
      <block id="13" user="GuendolenAverill184" by="Clive" timestamp="2012-03-01T18:47:32Z" expiry="infinity" reason="" nocreate="" autoblock="" />
      <block id="11" user="MamieCalvin929" by="Clive" timestamp="2012-03-01T13:48:54Z" expiry="infinity" reason="" nocreate="" autoblock="" />
      <block id="9" user="23wfsda" by="Clive" timestamp="2012-03-01T08:57:08Z" expiry="infinity" reason="" nocreate="" autoblock="" />
      <block id="7" user="HughWarejzl" by="Clive" timestamp="2012-02-29T20:47:38Z" expiry="infinity" reason="" nocreate="" autoblock="" />
      <block id="5" user="MorrissetteEvenson351" by="Clive" timestamp="2012-02-28T08:54:33Z" expiry="infinity" reason="Inserting nonsense/gibberish into pages" nocreate="" autoblock="" />