Examine source code of Simple Light Gradient

{
  "theme": {
    "images": {
      "theme_frame": "header.jpg"
    },
    "colors": {
      "frame": "#d4d4d4",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Simple Light Gradient",
  "manifest_version": 2,
  "description": "It's a simple gradient; no clutter."
}