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>
    <blocks bkcontinue="20130126144016|6535" />
  </query-continue>
  <query>
    <blocks>
      <block id="6559" user="Hakans" by="Andric" timestamp="2013-10-15T01:28:06Z" expiry="infinity" reason="Спам-ссылки на внешние сайты" nocreate="" autoblock="" noemail="" />
      <block id="6557" user="DanutafyyvfulicxSkyes" by="Andric" timestamp="2013-10-15T01:25:40Z" expiry="infinity" reason="Спам-ссылки на внешние сайты" nocreate="" autoblock="" noemail="" />
      <block id="6551" user="Rapoo e2700" by="Andric" timestamp="2013-04-28T19:33:32Z" expiry="infinity" reason="Спам-ссылки на внешние сайты" nocreate="" autoblock="" noemail="" />
      <block id="6549" user="Joan8clocks" by="Andric" timestamp="2013-04-28T19:27:20Z" expiry="infinity" reason="спам" nocreate="" autoblock="" noemail="" />
      <block id="6547" user="ShelaiekixictxpCrutcher" by="Andric" timestamp="2013-04-28T19:22:55Z" expiry="infinity" reason="спам" nocreate="" autoblock="" noemail="" />
      <block id="6545" user="AlessandraionuhsutaxsdvltnvhuxxolcivbuxbcyyytLouthan" by="Andric" timestamp="2013-03-04T18:45:27Z" expiry="infinity" reason="Неприемлемое имя участника" nocreate="" autoblock="" noemail="" />
      <block id="6543" user="Winait digital camcorder" by="Andric" timestamp="2013-03-04T18:43:34Z" expiry="infinity" reason="Спам-ссылки на внешние сайты" nocreate="" autoblock="" noemail="" />
      <block id="6541" user="CharlaWal" by="Andric" timestamp="2013-01-26T21:02:10Z" expiry="infinity" reason="Спам-ссылки на внешние сайты" nocreate="" autoblock="" noemail="" />
      <block id="6539" user="Cojanlogin3" by="Andric" timestamp="2013-01-26T14:42:25Z" expiry="infinity" reason="Спам-ссылки на внешние сайты" nocreate="" autoblock="" noemail="" />
      <block id="6537" user="BrookeBon" by="Andric" timestamp="2013-01-26T14:41:51Z" expiry="infinity" reason="Спам-ссылки на внешние сайты" nocreate="" autoblock="" noemail="" />
    </blocks>
  </query>
</api>