Examine source code of Personalized Alarms Pro

{
  "name": "personalized-alarms",
  "version": "0.0.4",
  "description": "Create personalized alarms",
  "manifest_version": 2,
  "icons": {
    "16": "assets/images/icon16.png",
    "32": "assets/images/icon32.png",
    "48": "assets/images/icon48.png",
    "128": "assets/images/icon128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "browser_style": true
  },
  "permissions": [
    "storage",
    "alarms",
    "notifications"
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": false
  },
  "background": {
    "scripts": [
      "assets/js/background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{507e482f-8fc3-4b84-b891-38ffc37b6d9e}"
    }
  }
}