Examine source code of Darkened Void

{
  "name": "Darkened Void",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "firefox.png"
    },
    "colors": {
      "frame": "rgba(107, 131, 180, 1)",
      "tab_background_text": "rgba(106, 91, 143, 1)",
      "toolbar": "rgba(107, 131, 180, 1)",
      "bookmark_text": "rgba(182, 194, 219, 1)",
      "toolbar_field": "rgba(182, 194, 219, 1)",
      "toolbar_field_text": "rgba(110, 120, 180, 1)"
    }
  }
}