json - 清单不是有效的 JSON。行：10，列：3，根元素后的意外数据

Question

我正在学习开发 Google Chrome 扩展。在尝试加载我的扩展程序时，我收到以下消息：

Manifest is not valid JSON. Line: 10, column: 3, Unexpected data after root element.

下面是我的 manifest.json 文件：

{
  "manifest_version": 2,
  "name": "ShowTime",
  "description": "Extension to show the current date and time",
  "version": "1.2",
  "default_locale": "en",
  "description": "A plain text description",
  "icons": {
     "16": "icon16.png",
     "48": "icon48.png",
     "128": "icon128.png"
  },
  "browser_action": {
     "default_title": "ShowTime",
     "default_icon": "icon.png", 
     "default_popup": "popup.html"
  }
}