Examine source code of World Clock

{
  "manifest_version": 2,
  "name": "World Clock",
  "version": "1.0",
  "description": "A customizable world clock with up to 12 time zones, alarms, and multilingual support.",
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "64": "icons/icon64.png",
    "128": "icons/icon128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{34222326-eddf-49c3-bd31-8f3af43e28a8}"
    }
  },
  "web_accessible_resources": [
    "sounds/alarm01.mp3",
    "sounds/alarm02.mp3",
    "sounds/alarm03.mp3",
    "sounds/alarm04.mp3",
    "sounds/alarm05.mp3",
    "sounds/alarm06.mp3",
    "sounds/alarm07.mp3",
    "sounds/alarm08.mp3",
    "sounds/alarm09.mp3",
    "sounds/alarm10.mp3",
    "sounds/alarm11.mp3",
    "sounds/alarm12.mp3",
    "sounds/alarm13.mp3",
    "sounds/alarm14.mp3",
    "sounds/alarm15.mp3",
    "sounds/alarm16.mp3",
    "sounds/alarm17.mp3",
    "sounds/alarm18.mp3",
    "sounds/alarm19.mp3",
    "sounds/alarm20.mp3"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self';"
}