lib/PublicInbox/Spawn.pm | 1 +

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index c5a5c01223a6461b5ff13daf186241178f2f6344..66dce3353e3bd872fad51838a53200bf94f50632 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -144,6 +144,7 @@ 	no warnings 'once';
 	*public_inbox_fork_exec = *PublicInbox::SpawnPP::public_inbox_fork_exec
 }
 
+# n.b. we never use absolute paths with this
 sub which ($) {
 	my ($file) = @_;
 	foreach my $p (split(':', $ENV{PATH})) {