diff --git a/private/define-expanders.scrbl b/private/define-expanders.scrbl
index f25d175..daaddf4 100644
--- a/private/define-expanders.scrbl
+++ b/private/define-expanders.scrbl
@@ -22,6 +22,7 @@ expanders for use with other macros.
    identifier as a @code{id-expander?} for use in a transformer
    environment}
  @item{@code{expand-all-id-expanders} - a procedure bound at phase
+   @; TODO: expand-all-expanders-of-type is not documented
    level 1 that's equivalent to @racket[expand-all-expanders-of-type] with
    the @code{id-expander-type} as the type argument}
  ]}