.endd
+.option client_set_id authenticators string&!! unset
+When client authentication succeeds, this condition is expanded; the
+result is used in the log lines for outbound messasges.
+Typically it will be the user name used for authentication.
+
+
.option driver authenticators string unset
This option must always be set. It specifies which of the available
authenticators is to be used.
last of these is given in parentheses after the final address. The R and T
fields record the router and transport that were used to process the address.
+If SMTP AUTH was used for the deliver there is an additional item A=
+followed by the name of the authenticator that was used.
+If an authenticated identification was set up by the authenticator’s client_set_id
+option, this is logged too, separated by a colon from the authenticator name.
+
If a shadow transport was run after a successful local delivery, the log line
for the successful delivery has an item added on the end, of the form
.display