Examine source code of New item icon

{
  "manifest_version": 2,
  "name": "New item icon",
  "version": "1.0",
  "description": "A new item symbol is a small image (icon) that appears next to the product name or image, used to confirm that the product is 100% new, unused, and unopened.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Click me!"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{99178c01-492f-4439-b4ac-33e1ea998bba}"
    }
  }
}