Examine source code of Current Time Display

{
  "manifest_version": 2,
  "name": "Current Time Display",
  "version": "1.0",
  "description": "Displays the current time in your local time zone.",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c205ca1a-8c44-49f4-b93a-bd342e3292e5}"
    }
  }
}