Documentation/standards.perl | 4 ++++
 examples/unsubscribe.milter  | 7 ++++++-

diff --git a/Documentation/standards.perl b/Documentation/standards.perl
index 32003c912dee68f9e5ac4315dc51e22eb67c8e75..69568ceb3ce9887abd6804eddea3936e4dd73a69 100755
--- a/Documentation/standards.perl
+++ b/Documentation/standards.perl
@@ -62,6 +62,10 @@ 	# 8620 => JSON Meta Application Protocol (JMAP)
 	# 8621 => JSON Meta Application Protocol (JMAP) for Mail
 	# ...
 
+	# examples/unsubscribe.milter and PublicInbox::Unsubscribe
+	2369 => 'URLs as Meta-Syntax for Core Mail List Commands',
+	8058 => 'Signaling One-Click Functionality for List Email Headers',
+
 	# TODO: flesh this out
 
 ];
diff --git a/examples/unsubscribe.milter b/examples/unsubscribe.milter
index 04a3976142da5dc29b805052b7ae105fb30767ea..216b0dddd0cf737e77dfb3780f48b48c5fc9d1cd 100644
--- a/examples/unsubscribe.milter
+++ b/examples/unsubscribe.milter
@@ -1,5 +1,5 @@
 #!/usr/bin/perl -w
-# Copyright (C) 2016-2021 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 use strict;
 use Sendmail::PMilter qw(:all);
@@ -96,6 +96,7 @@ 		return SMFIS_CONTINUE if archive_addr(lc($rcpt[0]));
 
 		my $unsub = $priv->{header}->{'list-unsubscribe'} || [];
 		my $n = 0;
+		my $added;
 		foreach my $u (@$unsub) {
 			# Milter indices are 1-based,
 			# not 0-based like Perl arrays
@@ -114,7 +115,11 @@ 			}
 			$v .= ",\n <https://$domain/u/$u/$list>";
 
 			$ctx->chgheader($k, $index, $v);
+			$added = 1;
 		}
+		# RFC 8058
+		$added and $ctx->addheader('List-Unsubscribe-Post',
+					'List-Unsubscribe=One-Click');
 	};
 	warn $@ if $@;
 	SMFIS_CONTINUE;