Most of that is probably attributable to being based on Kilo: https://github.com/antirez/kilo - a tiny text editor written by antirez who notably also created Redis. Antirez has a bunch of really interesting side projects if you dig into their github repo.

I like the extensive way Antirez has commented the data structures (and the rest of the codebase), something that was missing in the ptext code.

There's a "thanks" section at the end of the README which links to it, from what I can see.

They also thanks viewsourcecode.org but don't directly link to their excellent tutorial on how to build Kilo yourself: https://viewsourcecode.org/snaptoken/kilo/

thanks! i'll update my comment

Indeed. Also the default editor for ELKS (Linux for PC/XT and ATs).

Yep. Fit for my sole purpose of using other editors: Editing vim Makefile when I decide to recompile.