Starting form Special:Search contains <button role="button"> which is default and not recommended in HTML5:
Warning: The button role is unnecessary for element button.
From line 42, column 1554; to line 42, column 1692
utWidget'><button type='submit' tabindex='0' aria-disabled='false' value='' role='button' class='oo-ui-inputWidget-input oo-ui-buttonElement-button'><span
For the [[https://www.w3.org/TR/html5/forms.html#the-button-element | element <button>]] the attribute role="button" is not recommended to set because it is the default value.
The elements with strong native semantics which are not supposed to carry role=button:
- <button>
- <input type="button">
- <input type="image">
- <input type="reset">
- <input type="submit">