Examine source code of miku 2

{
  "theme": {
    "images": {
      "theme_frame": "Mikuver.8.png"
    },
    "colors": {
      "frame": "#f5eded",
      "tab_background_text": "#e0dddd"
    }
  },
  "version": "2.0",
  "name": "miku 2",
  "manifest_version": 2
}