Where is Dimmer (Gen 1) | NZW31 device handler?

I have an old NZW31 in-wall dimmer (1 gen).
I could not find device handler for it.
Thats the thing description:

But there are no link to device handler
Also, what is the difference NZW31 vs NZW31-sn?

this link does not work for me:
Thank you.

I think you can find the correct handlers in this repo https://github.com/InovelliUSA/SmartThingsInovelli/tree/master/smartapps/z-waveat

Here you go!