https://drafts.csswg.org/css-forms-1/#field-pseudos has the following inline issue:

Define something for the password visibility toggle for user agents implementing it?

I'd like to see this. We currently have ::-ms-reveal implemented in Edge Chromium for compat with Edge Legacy and Internet Explorer. It would be great to get it on a path to standardization.

See also: whatwg/html#7293