"listen on * port 80" means all v4 and v6 addresses these days.

OK benno

src/etc/examples/httpd.conf

@@ -1,8 +1,7 @@
-# $OpenBSD: httpd.conf,v 1.18 2018/03/23 11:36:41 florian Exp $
+# $OpenBSD: httpd.conf,v 1.19 2018/04/11 15:51:50 florian Exp $
 
 server "example.com" {
 	listen on * port 80
-	listen on :: port 80
 	location "/.well-known/acme-challenge/*" {
 		root "/acme"
 		root strip 2
@@ -14,7 +13,6 @@ server "example.com" {
 
 server "example.com" {
 	listen on * tls port 443
-	listen on :: tls port 443
 	tls {
 		certificate "/etc/ssl/example.com.fullchain.pem"
 		key "/etc/ssl/private/example.com.key"