What is the Notifications menu item?
As you can see on the image below, the User Menu contains an item called Notification. User Menu : Notifications Clicking on that menu item will bring you to your Active Notifications page. This is the place where you can manage all the notifications you have set in this site. Each time you select a checkbox in the Notification Options of a module and you hit Update Now, a new item is added to your Active Notifications.
This Q&A was found on XOOPS Web Application System : https://xoops.org/modules/smartfaq/faq.php?faqid=52