$ grep complete dbus complete -o nospace -F __dbus_send dbus-send The file should be named 'dbus-send' then, instead of 'dbus'. Otherwise, the completions aren't autoloaded.
$ qfile /usr/share/bash-completion/completions/dbus dev-libs/dbus-glib (/usr/share/bash-completion/completions/dbus)
fixed in 0.102