i use QED, btw
it's the predecessor to ed:
- https://en.wikipedia.org/wiki/QED_(text_editor)
- https://gunkies.org/wiki/QED_(text_editor)
- https://www.nokia.com/bell-labs/about/dennis-m-ritchie/qed.html
- https://github.com/arnoldrobbins/qed-archive
- https://github.com/phonologus/qed-new is a version with utf8 support which can be built on a modern system
