The sources for the awesome Dos Navigator are published on Github.

An updated fork named Necromancer's Dos Navigator [NDN] can be found here: http://ndn.muxe.com/

An alternative to DN/NDN, that is in active development, is Far Manager: https://www.farmanager.com/

All of them, especially Far, work well in ConEmu (https://conemu.github.io/) or cmder (https://cmder.app/)

Maybe interested people or nostalgic ones can help continue development on DN or NDN.