Lightweight Alarm clock

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Lightweight Alarm clock ",
  "version": "1.0.0",
  "description": "Alarm clock, countdown, interval timer",
  "manifest_version": 3,
  "author": "Roman",
  "permissions": [
    "alarms",
    "notifications"
  ],
  "background": {
    "service_worker": "background.js"
  },
  "action": {
    "default_popup": "index.html",
    "default_icon": "icon.png",
    "default_title": "Alarm clock"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.index.html/*"
      ],
      "js": [
        "background.js"
      ]
    }
  ]
}