Examine source code of Container icon

{
  "manifest_version": 2,
  "name": "Container icon",
  "version": "1.0",
  "description": "The container symbol is a symbol representing a container, usually a carton/box used in contexts such as: Delivery, transportation, Storage, packaging, Warehouse management, logistics, Indicating the product is still in the box.",
  "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": "{83c76083-c7dd-4460-a15b-35c697ebaf1e}"
    }
  }
}