Examine source code of IceFox

{
  "name": "external-content.duckduckgo.com",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "external-content.duckduckgo.com.jpg"
    },
    "colors": {
      "frame": "rgba(89, 121, 194, 1)",
      "tab_background_text": "rgba(93, 96, 240, 1)",
      "toolbar": "rgba(97, 166, 235, 0.6)",
      "bookmark_text": "rgba(69, 104, 230, 1)",
      "toolbar_field": "rgba(125, 183, 240, 0.66)",
      "toolbar_field_text": "rgba(27, 62, 143, 1)",
      "tab_line": "rgba(109, 179, 232, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2a48126e-f9d6-4738-b4f1-e4b7bf02929b}"
    }
  }
}