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.
meta
viewport text to normative and add two issues. One to test if the description matches reality. Second is while we spec with the same mechanism there may be differences as we tease out compat.overflow-style: auto|auto-hide|overlay
to allow authors more control over scrollbars while balancing out the desires of implementors to control their scrollbars.