Hi, I watched Lars' presentation on TECO and a couple of very early Emacsen (late 70s and early 80s).
https://www.youtube.com/watch?v=xdJtANtJMIg
I think that gave me all the context I needed in terms of that period and those early versions. ❤️ I might try a slightly more modern GNU Emacs (from the 90s), following the links you mentioned.
Ty!