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.
margin-break: [ auto | discard | keep ] to control margin-before at page-breaks. auto is behavior described above. Can add second value to control margin-after (defaults to discard).page-break-before, page-break-after: column to force column breaks, other values apply to column breaking as well as pages.image-resolution: normal | [ <dpi> || auto ] Rationale: Removes unused combinations and unnecessary comma.image-resolution: auto with image-resolution: from-image. Rationale: auto vs. normal is hard to understand. (‘normal’ is 1 pixel == 1px).image-resolution applies to all images and we will introduce functional notation in the future to allow setting resolution on a per-image basis.