Examine source code of Custom New Tab Page

{
  "browser_action": {
    "default_title": "__MSG_appName__",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "default_locale": "en",
  "description": "__MSG_extDes__",
  "icons": {
    "128": "icon_128.png"
  },
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "permissions": [
    "activeTab",
    "storage",
    "declarativeNetRequest",
    "alarms"
  ],
  "version": "1.0.8",
  "browser_specific_settings": {
    "gecko": {
      "id": "{6fe1f1ed-a284-4803-92b7-a7ceb55cfe7d}"
    }
  }
}