Examine source code of To next stage.

{
  "theme": {
    "images": {
      "theme_frame": "1014-akairkirei8da---oo.jpg"
    },
    "colors": {
      "frame": "#dbe3d6",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "To next stage.",
  "manifest_version": 2,
  "description": "。。丘の上にのぼります。。"
}