master-server/deps/curl/docs/cmdline-opts/mail-auth.md

c	SPDX-License-Identifier	Long	Arg	Protocols	Help	Added	Category	Multi	See-also	Example
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.	curl	mail-auth	<address>	SMTP	Originator address of the original email	7.25.0	smtp	single	mail-rcpt mail-from	--mail-auth user@example.come -T mail smtp://example.com/

--mail-auth

Specify a single address. This is used to specify the authentication address (identity) of a submitted message that is being relayed to another server.