This is a page from the Cascading Style Sheets Working Group Blog. Some other places to find information are the “current work” page, the www-style mailing list, the Future of CSS syndicator, and the issue list on Github.
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.
box-shadow
from CSS Backgrounds and Borders Level 3: work on box-shadow
outside the module for the time being, possibly re-merge with draft later. Rationale: drop-shadows seem to need a lot more discussion, but the rest of the draft is ready to move on.border-image
resizes to fit small boxes the same way as border-radius
(proportional in both dimensions)