Examine source code of Subtle Orange Dark

{
  "name": "Subtle Orange Dark",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "Background.png"
    },
    "colors": {
      "frame": "rgba(20, 20, 20, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(51, 51, 51, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(23, 23, 23, 1)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(255, 60, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{aca59689-9c55-4267-b442-be3d5e93d40a}"
    }
  }
}