Should <input type=hidden> match :optional? #11273
Description
What is the issue with the HTML Standard?
The :optional pseudo-class is specified to only match input elements to which the required attribute applies, this excludes hidden inputs.
However, https://wpt.live/html/semantics/selectors/pseudo-classes/required-optional-hidden.html expects hidden inputs to match the :optional pseudo-class regardless of any required attribute, and both Chromium and Webkit implement that behaviour while Firefox does not.