// Get an instance of JRegistry $registry = JRegistry::getInstance(); // Set a default value for a key $registry->set('userprefs.enable_notifications', true); // Get a value for a key, or use the default if it doesn't exist $enableNotifications = $registry->get('userprefs.enable_notifications', true); // Update a value for a key $registry->set('userprefs.enable_notifications', false);In this example, JRegistry is used to store and manage user preference settings. The `getInstance()` method is called to retrieve an instance of JRegistry, and the `set()` and `get()` methods are used to store and access values for the `userprefs.enable_notifications` key. JRegistry is part of the Joomla Platform, which is a PHP package library that provides a suite of tools and frameworks for building web applications.