Reaction score: 329
I believe there was agreement to continue to provide svn updates through the life of 12.x.
Exactly. Some people have known about this for a minimum of 3.5 years (assuming the PR meant 10.4). Expecting users to read every bug report to find which happen to mention changes that break existing procedures isn't reasonable. This reminds me of a Douglas Adams quote.
I specifically checked the official master FreeBSD copy of the Handbook from: https://download.freebsd.org/ftp/doc/en/books/handbook/book.pdf (no hotlink title so the URL is visible in the post). Word search in Acrobat: etcupdate, 0 matches; mergemaster, 25 matches.
I always do read the release notes and errata, and I don't remember seeing it. That doesn't mean there never was one, of course. Even if there was, this is the sort of thing that should remain in the release notes until the change happens (and then the release notes should say that as of the version the release notes pertain to, things have changed).