Examine source code of World Clock

{
  "manifest_version": 3,
  "name": "World Clock",
  "version": "2.0",
  "author": "Nilotpal",
  "action": {
    "default_popup": "time.html",
    "default_icon": "icon.png",
    "default_title": "WC1"
  },
  "background": {
    "scripts": [
      "clock2.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "chandranilotpal21@gmail.com",
      "strict_min_version": "42.0"
    }
  }
}