Examine source code of Yellow-Orange Gradient

{
  "theme": {
    "images": {
      "theme_frame": "Sinttulo-1.jpg"
    },
    "colors": {
      "frame": "#888888",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Yellow-Orange Gradient",
  "manifest_version": 2,
  "description": "Yellow and orange theme with the Firefox icon in warm colours at right..."
}