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>
    <blocks>
      <block id="8" user="123.227.46.152" by="Hiro kaji" timestamp="2023-05-21T03:46:52Z" expiry="infinity" reason="" nocreate="" noemail="" />
      <block id="7" user="5.188.211.170" by="Hiro kaji" timestamp="2017-09-19T05:54:24Z" expiry="infinity" reason="ページへ無意味な/意味不明な内容の挿入" nocreate="" noemail="" />
      <block id="5" user="46.161.14.99" by="Hiro kaji" timestamp="2017-09-03T11:52:19Z" expiry="infinity" reason="" nocreate="" />
      <block id="1" user="88.198.155.51" by="Hiro kaji" timestamp="2014-05-05T21:28:31Z" expiry="infinity" reason="ページへ無意味な/意味不明な内容の挿入" nocreate="" />
    </blocks>
  </query>
</api>