When creating a Skylands world type, the world generates without surface dirt or grass and instead generates stone, ores, and hills made of Endstone.

The only trees that generate in this world are trees that are part of village spawns.

World shown in attached screenshots are of a Plains biome Skyland world.

Steps to reproduce:

1) Download Minecraft snapshot version 21w42a

2) Create a new world & select Skylands world type

3) Generate the world