Examine source code of Download Done Chime

{
  "manifest_version": 2,
  "name": "Download Done Chime",
  "version": "1.0",
  "description": "Phát âm báo kiểu 'download manager classic' khi tải file xong.",
  "permissions": [
    "downloads",
    "storage"
  ],
  "background": {
    "page": "background.html"
  },
  "browser_action": {
    "default_title": "Download Done Chime",
    "default_popup": "popup.html",
    "default_icon": "icons/icon48.png"
  },
  "icons": {
    "48": "icons/icon48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9167803d-522c-4c79-8f09-460fa61f29fe}"
    }
  }
}