As far as I can tell it's a limited subset of REXX called KEXX: https://en.wikipedia.org/wiki/XEDIT#KEXX https://en.wikipedia.org/wiki/XEDIT#KEXX but I'm not su

As far as I can tell it's a limited subset of REXX called KEXX: https://en.wikipedia.org/wiki/XEDIT#KEXX https://en.wikipedia.org/wiki/XEDIT#KEXX but I'm not sure; I can't find any specific details. But pretty much, yes. This article: https://www.nytimes.com/2017/09/28/magazine/the-mind-of-john-mcphee.html https://www.nytimes.com/2017/09/28/magazine/the-mind-of-john... says he's one of the few remaining users.