Examine source code of Mail Ping Fixer

{
  "manifest_version": 2,
  "name": "Mail Ping Fixer",
  "version": "1.0",
  "description": "Bổ sung âm thanh thông báo khi webmail có thư mới.",
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://mail.google.com/*",
        "*://outlook.live.com/*",
        "*://*.yahoo.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "mail-ping-fixer@addon.mozilla",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}