Supersite for Windows posted an analysis on the Windows 9 Technical Preview Virtual Desktops and Notification Center Video Leaks
As noted previously, Windows Phone 8.1 introduces a notification center feature called Action Center. But I was curious what they would name this feature in Big Windows since we've had a feature there called Action Center since Windows 7, and it has nothing to do with notifications. Based on a new Winfuture.de video, the new notification center in Windows 9 is not called Action Center. It's just called ... Notifications.Windows 9 Technical Preview Virtual Desktops and Notification Center Video Leaks: An Analysis
This notification center commingles classic desktop notifications ("Safe to remove hardware," and so on) with Modern app and system notifications. And its access through a system tray icon that, yes, is identical to the Action Center icon in Windows Phone 8.1. When you click it, the Notifications window appears.