Reminders
In case you have the Reminder for Jira app on your instance and it is enabled, you can display the reminders within calendars.
Navigate to Calendar settings → Calendar Layout and tick the "Show My Reminders" checkbox – the reminders available to you will be displayed in the calendar grid (each user can browse their reminders).
If a user has permission to edit and delete a reminder, they can perform those actions directly in the Calendar.