It's sway with eye-candy. (Or, if you don't know about sway, the Wayland version of i3 — also with eye-candy).
If you're still not sure, you're simply not the target audience, these things almost always require further learning and customization, so some level of gate-keeping from the start is helpful.
Yep this - you’re not the target audience. It’s a UI desktop layer for Linux, made for the enthusiast.
But also, OP posted a link that is not mobile friendly (at least on safari) and doesn’t say much about what this is. The main page does a fine job though (for those would care I guess).
