Examine source code of Night Milk

{
  "theme": {
    "images": {
      "theme_frame": "header_onedaydream.jpg"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "#f2f1c9"
    }
  },
  "version": "2.0",
  "name": "Night Milk",
  "manifest_version": 2,
  "description": "変な夢を見て起きた夜に飲む、ミルクのイメージ"
}