dev/defs/bones/root_bone.json

{
  "name": "RootBone",
  "key": {
    "int": 41,
    "string": "rootbone"
  },
  "extends": "bones/bone.json",
  "properties": {
    "x": {
      "type": "double",
      "initialValue": "0",
      "overrideGet": true,
      "animates": true,
      "group": "position",
      "key": {
        "int": 90,
        "string": "x"
      }
    },
    "y": {
      "type": "double",
      "initialValue": "0",
      "overrideGet": true,
      "animates": true,
      "group": "position",
      "key": {
        "int": 91,
        "string": "y"
      }
    }
  }
}