one of the devs here, and yeah fair, the about page says nothing. it's a custom rom that makes non-pixel phones run like a pixel: aosp + gapps + the pixel exclusive features
put simpler, this replaces the stock android your manufacturer ships
So I guess the point of this is to provide a Pixel-like experience to non-Pixel phones? It's a cool idea but I think I'll personally stick with GrapheneOS for my next phone.
It's always surprising how many people who like to tinker with their devices also deliberately want to tie themselves more into the Google ecosystem. I would've guessed that the Venn diagram of these two types of people wouldn't have much overlap, but the ROM's popularity kind of speaks for itself.
Tbf I (degoogled Graphene/ex-LOS user for more than a decade) can definitely see why you would rather have the mostly-AOSP-native Pixel experience on your smartphones than completely enshittified UIs that Samsung or Huawei provide...
put simpler, this replaces the stock android your manufacturer ships