dbus-monitor --system

signal sender=org.freedesktop.DBus -> dest=:1.23 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameAcquired
   string ":1.23"
signal sender=org.freedesktop.DBus -> dest=(null destination) path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
   string ":1.24"
   string ""
   string ":1.24"
signal sender=org.freedesktop.DBus -> dest=(null destination) path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameOwnerChanged
   string ":1.24"
   string ":1.24"
   string ""