Examine source code of Event Countdown Timer

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "1.0",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d3f7b2a8-c3e5-2f5c-a5d5-b9e1f7b3c1a6}"
    }
  },
  "permissions": [
    "storage",
    "notifications",
    "alarms"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "128": "icons/icon128.png"
    }
  }
}