Table with header cells in the first column only

For this type of table, you have to set the @rowheader="firstcol" attribute on the <table> element to identify the header column.

Table 1. Example: Oxygen Events
Event	Evolution of TC 2018	Markup UK	Balisage 2018 - The Markup Conference
Date	May 31 - June 1, 2018	June 9 - 10, 2018	July 31 - August 3, 2018
Location	Sofia, Bulgaria	London, United Kingdom	Rockville, Maryland, USA

<table rowheader="firstcol">
  <title>
    <b>Oxygen Events</b>
  </title>
  <tgroup cols="4">
    <colspec colname="COLSPEC0" colwidth="1*"/>
    <colspec colname="COLSPEC1" colwidth="1.1*"/>
    <colspec colname="newCol3" colwidth="1*"/>
    <colspec colname="newCol4" colwidth="1*"/>
    <tbody>
      <row>
        <entry>Event</entry>
        <entry>Evolution of TC 2018</entry>
        <entry>Markup UK</entry>
        <entry>Balisage 2018 - The Markup Conference</entry>
      </row>
      <row>
        <entry>Date</entry>
        <entry>May 31 - June 1, 2018</entry>
        <entry>June 9 - 10, 2018</entry>
        <entry>July 31 - August 3, 2018</entry>
      </row>
      <row>
        <entry>Location</entry>
        <entry>Sofia, Bulgaria</entry>
        <entry>London, United Kingdom</entry>
        <entry>Rockville, Maryland, USA</entry>
      </row>
    </tbody>
  </tgroup>
</table>