Ayatana Indicator that collects messages that need a response

 A place on the user's desktop that collects messages that need a response.
 .
 This menu provides a condensed and collected view of all of those messages
 for quick access, but without making them annoying in times that you want
 to ignore them.
 .
 Ayatana Indicators are only available on desktop environments that
 provide a renderer for system indicators (such as MATE, Xfce, Lomiri,
 etc.).