LayerTree.layerTreeDidChange

{
  "name": "layerTreeDidChange",
  "parameters": [
    {
      "name": "layers",
      "type": "array",
      "items": {
        "$ref": "Layer"
      },
      "optional": true,
      "description": "Layer tree, absent if not in the comspositing mode."
    }
  ]
}