dsurround.cfg:

biomes {
    # Configuration files for configuring Biome Registry [default: ]
    S:"Config Files" <
        bop.json
     >

bop.json:

    # Biome alias list [default: ]
    S:"Biome Alias" <
     >
}


{
    "biomes":[
        {
            "biomeName":"ominouswoods",
	    "fogDensity":0.5
	}
    ]
}