"Calendar notifications" refers to alerts or reminders that are provided by a digital calendar application to inform users about upcoming events, meetings, or appointments. Full definition
See call, text or calendar notifications on screen & get push notifications from your favorite apps. (fitbit.com)
This release includes a number of other features as well, such as lock screen calendar notifications and improvements to badge notifications. (neowin.net)
It also shows notifications and when the phone is unlocked, it also shows shortcuts, lets you control music, and shows calendar notifications. (fortheloveoftech.com)