Examine source code of Default Browser Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Default Browser Dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(28, 27, 34)",
      "toolbar_text": "rgb(228, 235, 246)",
      "frame": "rgb(43, 42, 51)",
      "tab_background_text": "rgb(228, 235, 246)",
      "toolbar_field": "rgb(43, 42, 51)",
      "toolbar_field_text": "rgb(228, 235, 246)",
      "tab_line": "rgb(28, 27, 34)",
      "popup": "rgb(28, 27, 34)",
      "popup_text": "rgb(228, 235, 246)",
      "ntp_background": "rgb(28, 27, 34)",
      "popup_border": "rgb(43, 42, 51)",
      "popup_highlight_text": "rgb(228, 235, 246)",
      "popup_highlight": "rgb(63, 63, 72)",
      "sidebar_border": "rgb(43, 42, 51)",
      "sidebar_highlight_text": "rgb(228, 235, 246)",
      "sidebar_highlight": "rgb(82, 82, 94)",
      "sidebar_text": "rgb(228, 235, 246)",
      "sidebar": "rgb(28, 27, 34)",
      "toolbar_bottom_separator": "rgb(43, 42, 51)",
      "toolbar_field_border_focus": "rgb(43, 42, 51)",
      "toolbar_field_border": "rgb(28, 27, 34)",
      "toolbar_field_focus": "rgb(43, 42, 51)",
      "toolbar_field_highlight": "rgb(63, 63, 72)",
      "toolbar_field_separator": "rgb(228, 235, 246)",
      "toolbar_field_text_focus": "rgb(228, 235, 246)",
      "tab_loading": "rgb(28, 27, 34)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{51edf71a-1bbb-47d6-b89a-8b0b6a1d60b0}"
    }
  }
}