dbus-x11 1.8.12-1ubuntu2 (amd64 binary) in ubuntu vivid

 D-Bus is a message bus, used for sending messages between applications.
 Conceptually, it fits somewhere in between raw sockets and CORBA in
 terms of complexity.
 .
 This package contains the dbus-launch utility which is necessary for
 packages using a D-Bus session bus.
 .
 See the dbus description for more information about D-Bus in general.