There are likely 100x (if not more) links to CSS2.x fragment links from before 2016 than after, and thus it makes a lot more sense to restore the 2011 REC fragment anchors to keep more fragment links working on the web, especially those that were referencing /TR/CSS2/somepage.html#somefragment or /TR/CSS21/somepage.html#somefragment which redirect to the latest version.
PROPOSED: Restore fragment identifiers in CSS2.x to those in the CSS2.1 REC published in 2011.