Missing man page for notify-send
Originally reported October 2015 on https://bugzilla.gnome.org/show_bug.cgi?id=757151
Debian ships a man page that could be used / adopted upstream.
From https://packages.debian.org/sid/libnotify-bin (http://http.debian.net/debian/pool/main/libn/libnotify/libnotify_0.7.6-2.debian.tar.xz).