standalone StatusNotifierItem/AppIndicator tray

 gtk-sni-tray provides a StatusNotifierHost widget written using the
 gtk+3 bindings for haskell provided by gi-gtk. It also provides a
 simple standalone executable, gtk-sni-tray-standalone, that is
 configured with command line arguments. This executable will run the
 aforementioned widget by itself in a strut window, on each monitor
 for each it is requested.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.