Examine source code of Deep rust gradient

{
  "name": "Deep rust gradient",
  "manifest_version": 2,
  "version": "3.0",
  "theme": {
    "images": {
      "theme_frame": "gradient.jpg"
    },
    "colors": {
      "frame": "rgba(128, 128, 128, 1)",
      "tab_background_text": "rgba(56, 43, 27, 1)",
      "toolbar": "rgba(61, 50, 28, 0.58)",
      "bookmark_text": "rgba(173, 142, 102, 1)",
      "toolbar_field": "rgba(145, 125, 98, 0.7)",
      "toolbar_field_text": "rgba(61, 50, 32, 1)",
      "tab_line": "rgba(163, 119, 85, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2a250511-1e93-42c5-8040-cf9c621d988e}"
    }
  }
}