lib/PublicInbox/Eml.pm | 1 +

diff --git a/lib/PublicInbox/Eml.pm b/lib/PublicInbox/Eml.pm
index 81a6632b7720c711c75562eb3a1bb99b2a98b01d..0697c3a50babd4a328a64905e7af07474d6b0afa 100644
--- a/lib/PublicInbox/Eml.pm
+++ b/lib/PublicInbox/Eml.pm
@@ -234,6 +234,7 @@ # same usage as PublicInbox::MsgIter::msg_iter
 # $cb - user-supplied callback sub
 # $arg - user-supplied arg (think pthread_create)
 # $once - unref body scalar during iteration
+# $all - used by IMAP server, only
 sub each_part {
 	my ($self, $cb, $arg, $once, $all) = @_;
 	my $p = mp_descend($self, $once // 0) or