You can find it at https://github.com/happenslol/qwer . Be warned though, it's heavily lacking in documentation and polish, although all core features are working. I've just added a bit of info to the Readme, hit me up if you have any questions.
As an example I use fnm (https://github.com/Schniz/fnm) for managing JavaScript versions. It runs so fast (compared to nvm) I'm inclined to think something went wrong and it silently failed, but it never does!