dbus-x11 1.1.1-3ubuntu2 (amd64 binary) in ubuntu gutsy

 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.