Also, regarding that big beautiful
screenshot, it looks like there's a green type of city-state below the religious/white one, since it has the black outer border (or is it scientific/blue and the yellow'ish map effect is blending with it? *EDIT: Though, rivers don't seem to be affected much by the map tint.*). If it is, I'm guessing that's the food one. The bonus style of all the city-states is also similar to the old Maritime one, though, I'm guessing a food CS in Civ6 would be named something different.
Though, if it is a city-state, I wonder why it already popped-out two tiles while the religious one hasn't expanded at all. Maybe the green one has a resource which provides a good amount of culture.
Or, maybe this entire screenshot is just artificially made. Pretty likely, and I hope so, because the border expansion of China's lower city may have grabbed 3rd ring mountain tiles before perfectly good river land right in the 2nd ring, haha.