Examine source code of Favicon Detector

{
  "name": "__MSG_extensionName__",
  "author": "BlackGlory",
  "version": "4.1.5",
  "manifest_version": 3,
  "default_locale": "en",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "16": "assets/images/icon-16.png",
    "32": "assets/images/icon-32.png",
    "48": "assets/images/icon-48.png",
    "64": "assets/images/icon-64.png",
    "128": "assets/images/icon-128.png"
  },
  "action": {
    "default_title": "__MSG_extensionBrowserActionTitle__",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "assets/images/icon-16.png",
      "32": "assets/images/icon-32.png",
      "48": "assets/images/icon-48.png",
      "64": "assets/images/icon-64.png",
      "128": "assets/images/icon-128.png"
    }
  },
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5eddefd2-1d1e-4e7b-b9b5-1da06d23588b}"
    }
  }
}