Examine source code of Vocaloid Night Sky

{
  "theme": {
    "images": {
      "theme_frame": "personaprac.png"
    },
    "colors": {
      "frame": "#dae1e6",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Vocaloid Night Sky",
  "manifest_version": 2,
  "description": "My first firefox persona.\nFeel free to use it.\nBased on anime.\nHatsune Miku"
}