diff --git a/collects/web-server/docs/reference/private.scrbl b/collects/web-server/docs/reference/private.scrbl
index 4717b1ff12..cd10c0c9eb 100644
--- a/collects/web-server/docs/reference/private.scrbl
+++ b/collects/web-server/docs/reference/private.scrbl
@@ -143,6 +143,8 @@ This dispatching server component is useful on its own.
 @file{private/dispatch-server-unit.ss} provides the unit
 which actually implements a dispatching server.
 
+@; XXX Talk about how threads and custodians are used.
+
 @defthing[dispatch-server\@ (unit/c (tcp^ dispatch-server-config^) (dispatch-server^))]{
  Runs the dispatching server config in a very basic way, except that it uses
  @secref["connection-manager.ss"] to manage connections.