Examine source code of Copper

{
  "name": "Copper",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "images/theme_frame.jpeg"
    },
    "colors": {
      "frame": "rgb(66, 116, 201)",
      "tab_background_text": "rgb(173, 157, 255)",
      "toolbar": "rgba(223, 217, 242, 0.01)",
      "bookmark_text": "rgb(250, 174, 147)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{89595531-9ed6-468d-8d6c-86826fa73272}"
    }
  }
}