Examine source code of IP Change Notifier

{
  "manifest_version": 2,
  "name": "IP Change Notifier by #beaubhavik",
  "description": "Tracks your IP address and notifies you if it changes.",
  "version": "1.0.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "ipnotifier@spiderdunia.com",
      "strict_min_version": "79.0"
    }
  },
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "permissions": [
    "notifications",
    "tabs",
    "https://api.ipify.org/"
  ],
  "browser_action": {
    "default_icon": {
      "48": "icons/icon48.png",
      "96": "icons/icon96.png"
    },
    "default_title": "IP Change Notifier",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background/background.js"
    ]
  }
}