JED 1.6.0+ - Custom colors example

{
    "dimension": [
        {
            "dim": 5,
            "dimensiontype": {
                "name": "Custom Dimension",
                "worldprovider": "WorldProviderSurfaceJED"
            },
            "worldinfo_onetime": {},
            "jed": {
                "CloudColor": "66DDFF",
                "FogColor": "66FFDD",
                "SkyColor": "77CCEE",
                "Colors": {
                    "FoliageColors": [
                        { "biome_regex": "minecraft:.*","color": "F91010" },
                        { "biome": "minecraft:forest",  "color": "4444AA" },
                        { "biome": "minecraft:desert",  "color": "551111" }
                    ],
                    "GrassColors": [
                        { "biome": "minecraft:ocean",   "color": "119999" }
                    ],
                    "WaterColors": [
                        { "biome": "minecraft:mesa",    "color": "CC55CC" }
                    ]
                }
            }
        }
    ]
}