This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
http://dev.w3.org/csswg/css-cascade/#preshint says [[ The UA may choose to honor presentational hints in a source document’s markup, for example the bgcolor attribute or <s> element in [HTML5]. ]] but <s> doesn't have preshints defined in HTML, just UA styles. If you want a different example, search for "presentational hint" in http://www.whatwg.org/specs/web-apps/current-work/multipage/rendering.html#rendering