libnotify4 binary package in Ubuntu Oracular arm64

 A library that sends desktop notifications to a notification daemon, as
 defined in the Desktop Notifications spec. These notifications can be
 used to inform the user about an event or display some form of
 information without getting in the user's way.
 .
 This package contains the shared library. To actually display the
 notifications, you need to install the package notification-daemon or
 any other desktop environment implementing the FreeDesktop notification
 daemon specification.

Source package