Examine source code of Current Time Popup

{
  "manifest_version": 2,
  "name": "Current Time Popup",
  "version": "1.0",
  "description": "View the current time instantly in the popup.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f69812e5-5bff-4330-ae35-f461422ff481}"
    }
  }
}