BlueMap/BlueMapCore/src/main/resourceExtensions/mc1_18/assets/minecraft/blockstates/birch_wall_sign.json

{
    "variants": {
        "facing=south": { "model": "block/sign/wall_birch" },
        "facing=west": { "model": "block/sign/wall_birch", "y": 90 },
        "facing=north": { "model": "block/sign/wall_birch", "y": 180 },
        "facing=east": { "model": "block/sign/wall_birch", "y": 270 }
    }
}