That is also what I believe, but what to do with the BiomeProvider? What can I add to it to modified the biomes?
I tried to simply change the biome list but it doesn't work.
public BiomeProviderCustom(OverworldBiomeProviderSettings settingsProvider)
{
WorldInfo worldinfo = settingsProvider.getWorldInfo();
OverworldGenSettings settings = settingsProvider.getGeneratorSettings();
Layer[] alayer = LayerUtil.buildOverworldProcedure(worldinfo.getSeed(), worldinfo.getGenerator(), settings);
this.genBiomes = alayer[0];
this.biomeFactoryLayer = alayer[1];
}