I wanted to suggest to add a system for whitelisting/blacklisting some specific biomes for underground biomes. It would be particularly usefull for dimension with unique biome, when you want to generate underground biome in this dimension, but not all the biomes which are registered with the same type than the targetted one.

You can use the dimension config for that, just put it in whitelist.

I think you didn't get what I meant, sorry if I talk badly. If for exemple I want some underground biome generate in a dimension like the underworld from LightiningCraft, and it registers the unique biome of the dimension as SPOOKY, I have to add this biomes type to the whitelist of biome types of this underground biome. But then the underground biome will generate in all SPOOKY biomes without caring of the dimensions. It would be awesome to be able to config differently the laws of generation depending of the dimension.

That is exactly what I'm saying. Underground biomes have a dimension config already. You can make it so it only spawns in that dimension.

Oh ok, how do you do that ?

Every underground biome has this in their config. Just change it there: