Examine source code of IP Finder

{
  "manifest_version" : 2 ,
  "name" : "IP Finder",
  "version" : "1.8.7",
  "description" : "Shows your public and local IP addresses.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{885843a9-e30a-485f-8db4-ea33d728bbd4}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions" : [
    "activeTab" ,
    "storage" 
  ],
  "browser_action" : {
    "default_icon" : {
      "16" : "icons/icon-16.png",
      "48" : "icons/icon-48.png",
      "64" : "icons/icon-64.png",
      "128" : "icons/icon-128.png"
    },
    "default_title" : "IP Finder",
    "default_popup" : "popup/popup.html"
  },
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "icons" : {
    "16" : "icons/icon-16.png",
    "48" : "icons/icon-48.png",
    "64" : "icons/icon-64.png",
    "128" : "icons/icon-128.png"
  }
}