Guys, Yogscast figured out Pre3. Sky Dimension biomes do spawn, but in The Overworld as a yes. If you see any drastically strange chunks hanging over nothingness, that's the Sky Dimension Biome in testing. The Sky Dimension itself can be accessed in the code and was by GameChap, although the only difference currently is the sun it locked directly above you, there's clouds going through the lowest layers, and the sky looks different. Presume both the Sky Dimension Biomes and the Sky Dimension itself used together doesn't look as buggy.