yes, there are still systems around which cannot resolve service http by default

bin/varnishd/mgt/mgt_acceptor.c

@@ -164,7 +164,7 @@ tweak_listen_address(struct vsb *vsb, const struct parspec *par,
 	}
 	VTAILQ_INIT(&lsh);
 	for (i = 1; av[i] != NULL; i++) {
-		error = VSS_resolver(av[i], "http", tla_callback, av[i], &err);
+		error = VSS_resolver(av[i], "80", tla_callback, av[i], &err);
 		if (err != NULL) {
 			VSB_printf(vsb, "Invalid listen address ");
 			VSB_quote(vsb, av[i], -1, 0);

lib/libvcc/vcc_backend.c

@@ -54,7 +54,7 @@ Emit_Sockaddr(struct vcc *tl, const struct token *t_host,
 		bprintf(buf, "%s %s", t_host->dec, t_port->dec);
 	else
 		bprintf(buf, "%s", t_host->dec);
-	Resolve_Sockaddr(tl, buf, "http",
+	Resolve_Sockaddr(tl, buf, "80",
 	    &ipv4, &ipv4a, &ipv6, &ipv6a, &pa, 2, t_host, "Backend host");
 	ERRCHK(tl);
 	if (ipv4 != NULL) {