Examine source code of Vast stage.01

{
  "theme": {
    "images": {
      "theme_frame": "714--kumo-deki-yamagatatukuru---a1648-n.jpg"
    },
    "colors": {
      "frame": "#f7d8d4",
      "tab_background_text": "#030000"
    }
  },
  "version": "2.0",
  "name": "Vast stage.01",
  "manifest_version": 2,
  "description": "広大なステージ。０１"
}