Examine source code of Grassona

{
  "theme": {
    "images": {
      "theme_frame": "grassona_head.jpg"
    },
    "colors": {
      "frame": "#faf9da",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Grassona",
  "manifest_version": 2,
  "description": "The grass is always greener in Firefox.\n\n(Decorative summer or spring design using personal photography of garden plants.)"
}