Underlying API/ABI's get deprecated and eventually dropped, dependencies reach end-of-life and need to be replaced, and so on. But BSD vim (nvi) is maintained

Underlying API/ABI's get deprecated and eventually dropped, dependencies reach end-of-life and need to be replaced, and so on. But BSD vim (nvi) is maintained as part of the base systems of the BSDs, so it changes with system changes although it's in maintenance mode. E.g.: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/vi/ http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/vi/