Notify OSD
Canonicals on-screen-display notification agent, implementing the freedesktop.org Desktop Notifications Specification with semi-transparent click-through bubbles. These are designed to make you aware of something, without interrupting your work with a window you must close. Notify OSD presents these notifications as ephemeral overlays, which can be clicked through so they dont block your work. It queues notifications, to prevent them from flooding your screen.