Examine source code of IP Tracker

{
  "manifest_version" : 2 ,
  "name" : "IP Tracker",
  "version" : "1.0",
  "description" : "The Extension displays the IP address and flag of the associated country.",
  "browser_action" : {
    "default_popup" : "index.html"
  },
  "icons" : {
    "500" : "IP.png"
  },
  "content_scripts" : [
    {
      "matches" : [
        "*://*.mozilla.org/*" 
      ],
      "js" : [
        "popup.js" 
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4180b24e-f1d8-4e14-9a0e-dd58a86d5867}"
    }
  }
}