I bought the board here, but there are many other stores that sell it. FreeCAD 1.0 design files are included in case you need to do some modifications. It is a really handy board, because it can be connected directly to 220V without the need of a PSU.
I use it to control 3 speed + light celing fan using two pushbuttons and also a Telegram bot (so I can turn on/off the light and fan directly through Telegram) with this firmware (esp32 branch).
The author marked this model as their own original creation.