The first public release of GNU Emacs was 13.1 in March 1985. In July 1985, 16.56 was released with (RMS claims) all of Gosling's code replaced with new impleme

The first public release of GNU Emacs was 13.1 in March 1985. In July 1985, 16.56 was released with (RMS claims) all of Gosling's code replaced with new implementations. So we're talking about four months here. I think Gosling is claiming that some of his own code was still in there, regardless of what RMS said he rewrote. Just from casually poking the source code I can scrounge up [1], it doesn't look like there's any Gosling code in GNU 16.56 or later versions. But there's a lot of code in there so who knows. As a side note, as late as 1995 [2] Unipress was still trying to sell its Gosling derivative starting at $395 a seat. It had a nice list of features, including "Demonstrably better than vi", but I bet it didn't let you psychoanalyze Zippy. [1]: https://github.com/larsbrinkhoff/emacs-history https://github.com/larsbrinkhoff/emacs-history [2]: http://web.archive.org/web/19961125071933/http://www.unipress.com/cat/emacs.html http://web.archive.org/web/19961125071933/http://www.unipres...