Examine source code of night Rilakkuma

{
  "theme": {
    "images": {
      "theme_frame": "rilakchan.jpg"
    },
    "colors": {
      "frame": "#fac0f1",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "night Rilakkuma",
  "manifest_version": 2,
  "description": "my favourite kuma chan, this is the \"night\"theme"
}