Fieldset label (group-label)
Groups of related inputs (e.g., radio buttons, checkboxes) have a
<fieldset> and
<legend>.
Missing legend in fieldset:
This <fieldset> element does not have
a <legend>.
The (DOM/programmatic) structure of the above
fieldset looks like this:
<fieldset>
<label for="red">Red:</label>
<input type="radio" name="color" value="red" id="red" />
<br />
<label for="blue">Blue:</label>
<input type="radio" name="color" value="blue" id="blue" />
</fieldset>
Note: Automated testing should be possible. This violation can be
automatically detected by querying all
<fieldset> elements and checking if they
include a <legend> element.