what is legend tag do in html code example

Example 1: html legend

The HTML <legend> element represents a title caption for the content of 
its parent <fieldset>.

Example 2: making a legend in html

<ul class="legend">
    <li><span class="greendot"></span>High amounts of available beds</li><br></br>
    <li><span class="yellowdot"></span>Medium amounts of available beds</li><br></br>
    <li><span class="reddot"></span>Low amounts of available</li><br></br>
    <li><span class="blackdot"></span>Data of available beds N/A</li><br></br>
  </ul>
https://hospitable.live to see how it works