Do you want to know how the CSS WG works? Fantasai has written about:csswg, An Inside View of the CSS Working Group at W3C.
The CSS Working Group has published a Last Call Working Draft of the CSS Backgrounds and Borders Module Level 3
The 24 July 2012 Candidate Recommendation was returned to Last Call Working Draft, although most of it has been implemented, as implementation feedback suggested that some things could be improved. The changes, even though minor from the point of view of a user, require changes in implementations and thus the draft needs a new review.
The changes are explained in the specification itself. The most important ones are:
The end of the review period is 3 March 2014.