@b0rk there's a very old document called "ansicode.txt" that you may find interesting.

I first found it in the tmux repo, and later did a translation to markdown as my own form of active reading.

Which has the side benefit of letting me link to a section within it: https://github.com/jcorbin/anansi/blob/master/ansi/ansicode.md#c1-set-of-8-bit-control-characters-from-ansi-x364-1979