Examine source code of Firefox grappa

{
  "theme": {
    "images": {
      "theme_frame": "barfirefox.png"
    },
    "colors": {
      "frame": "#faa405",
      "tab_background_text": "#f5f2f2"
    }
  },
  "version": "2.0",
  "name": "Firefox grappa",
  "manifest_version": 2,
  "description": "Blue and orange grappa"
}