minecraft-bedrock-json-schemas/source/general/fog/identifier.json

{
  "$id": "blockception.minecraft.fog.identifier",
  "type": "string",
  "title": "Fog Identifier",
  "description": "A minecraft fog identifier",
  "examples": ["namespace:fog_name"],
  "pattern": "^[0-9a-zA-Z:_\\.\\-]+$"
}