Examine source code of Gnome

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Gnome",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(28, 28, 28)",
      "toolbar_text": "rgb(204, 203, 200)",
      "frame": "rgb(48, 48, 48)",
      "tab_background_text": "rgb(204, 203, 200)",
      "toolbar_field": "rgb(28, 28, 28)",
      "toolbar_field_text": "rgb(137, 255, 163)",
      "tab_line": "rgb(154, 153, 150)",
      "popup": "rgb(28, 28, 28)",
      "popup_text": "rgb(53, 132, 228)",
      "tab_loading": "rgb(154, 153, 150)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{68ae0d0d-7b48-4197-b89e-536dbc37deb4}"
    }
  }
}