Ominous's screenshot looks amazing. Does anyone know what (software/gui/manager/idk) is?

Even though I've been using Linux (Ubuntu) as my daily driver for the past several years, I really son't know too much about it such as how to ask the right question about desktop manager(?). The install instructions look detailed enough that I could probably figure it out. I will bookmark this, because I want to buy a laptop, amd it might be interesting to try to build/install this as an experiment first.