Property font-stretch doesn't exist : wider

Hello,

The CSS validator at http://jigsaw.w3.org/css-validator/ is reporting that

font-stretch: wider;

isn't a valid CSS 2.1 property.  The error message is:

Property font-stretch doesn't exist : wider

The validator accepts the same prpoerty in CSS 2.0 and CSS 3.0.  I'm not 
sure whether it is an oversight in the 2.1 spec or a bug in the 
validator.  If the former, it would be nice if the validator included a 
warning to say that the same is valid in 2.0 and 3.0 and give 
information about how to hint to browsers that one is using CSS 2.0 or 
CSS 3.0.

-- 
Michael