Examine source code of Darkly Hexagonal

{
  "name": "Dark Hexagon",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "unnamed.jpg"
    },
    "colors": {
      "frame": "rgba(13, 14, 15, 1)",
      "tab_background_text": "rgba(82, 80, 76, 1)",
      "toolbar": "rgba(20, 20, 20, 1)",
      "bookmark_text": "rgba(179, 179, 179, 1)",
      "toolbar_field": "rgba(38, 38, 38, 1)",
      "toolbar_field_text": "rgba(168, 168, 168, 1)"
    }
  }
}