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.
Brief discussion of direction, progress, and lack thereof.
display: svg and display: math or something similar at some point.
<iframe seamless>; CSS object negotiation algo needs an update to handle it.
display into multiple properties, particularly whether to split inner and outer display models into separate properties (display-inside/display-outside).
css-display-3 as a new ED.