Binary package “libnotify4” in ubuntu trusty

sends desktop notifications to a notification daemon

 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.