The “rowgroup” role is unnecessary for element “thead”.

The <thead> element is exposed with the ARIA role rowgroup by default, so role="rowgroup" on it only states its built-in role a second time.

Every HTML element maps to a default ARIA role, and the table sections share one: <thead>, <tbody> and <tfoot> are all row groups. Browsers already tell screen readers that the rows inside a <thead> form a group at the top of the table. An explicit role="rowgroup" changes nothing users can notice, which is why the validator reports it as a warning rather than an error.

You'll often see this in tables generated by page builders, table plugins or content copied from online editors, which tend to stamp a role onto every table part. The rowgroup role exists for tables made from generic elements such as <div>, where the markup gives assistive technology no clue about how the rows are grouped. A real <thead> already carries that meaning, so delete the attribute. While you're there, check the rest of the table. In a native <table>, a role on <tr>, <th> or <td> is reported as an error, so remove those in the same pass.

Invalid example

<table>
  <thead role="rowgroup">
    <tr>
      <th>Feature</th>
      <th>Included</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Backups</td>
      <td>Yes</td>
    </tr>
    <tr>
      <td>Priority support</td>
      <td>No</td>
    </tr>
  </tbody>
</table>

Valid example

<table>
  <thead>
    <tr>
      <th>Feature</th>
      <th>Included</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Backups</td>
      <td>Yes</td>
    </tr>
    <tr>
      <td>Priority support</td>
      <td>No</td>
    </tr>
  </tbody>
</table>

Learn more:

MDN Reference

ARIA: rowgroup role - MDN Web Docs

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MDN Reference

The Table Head element - MDN Web Docs

→

W3C Reference

ARIA in HTML

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