At first I thought this would be about pencil and paper RPG games, but looking at the website it is an alternative to RPG Maker, that has characters with a vaguely papery look to them due to use sprites in a 3-Dish setting.

It is written in Qt and produces games that run in Electron. So reasonably multiplatform. It is free if you don't make money with it, it looks like.

It is nice to see a largish project like this that blends Qt and Electron.