Examine source code of Stock Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "ClassicDarkFox",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(50, 50, 52)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(24, 24, 26)",
      "tab_background_text": "rgb(217, 217, 217)",
      "toolbar_field": "rgb(29, 31, 34)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgba(41, 82, 156, 0)",
      "popup": "rgb(74, 74, 79)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(93, 96, 101)",
      "button_background_hover": "rgb(75, 77, 82)",
      "frame_inactive": "rgb(29, 31, 34)",
      "icons_attention": "rgb(60, 186, 255)",
      "icons": "rgb(238, 238, 238)",
      "ntp_background": "rgb(25, 28, 34)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(78, 82, 89)",
      "popup_highlight_text": "rgb(255, 255, 255)",
      "popup_highlight": "rgb(27, 75, 131)",
      "sidebar_border": "rgb(0, 0, 0)",
      "sidebar_highlight_text": "rgb(128, 177, 223)",
      "sidebar_highlight": "rgb(10, 61, 112)",
      "sidebar_text": "rgb(255, 255, 255)",
      "sidebar": "rgb(34, 36, 39)",
      "tab_loading": "rgb(121, 164, 255)",
      "tab_selected": "rgb(38, 53, 80)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgb(59, 60, 64)",
      "toolbar_field_border_focus": "rgb(9, 82, 193)",
      "toolbar_field_border": "rgb(23, 23, 26)",
      "toolbar_field_focus": "rgb(42, 42, 46)",
      "toolbar_field_highlight_text": "rgb(255, 255, 255)",
      "toolbar_field_highlight": "rgb(37, 88, 147)",
      "toolbar_field_text_focus": "rgb(226, 226, 226)",
      "toolbar_top_separator": "rgba(38, 43, 55, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c8bbd92a-177c-40fe-a365-41f199c52c8c}"
    }
  }
}