diff --git a/src/binary_formats.ml b/src/binary_formats.ml
index 27a2648a..94962fda 100644
--- a/src/binary_formats.ml
+++ b/src/binary_formats.ml
@@ -34,7 +34,8 @@
       with the algorithm specified in RFC 8785. The resulting bytes are
       terminated with a single 0-byte and then hashed with SHA512."
    - from the code it looks like its the same for all stringy-strings
-     !! not strings that are raw-bytes-data-like
+     ! not strings that are raw-bytes-data-like
+     ? only for "HashCode" and "ShortHashCode"
  *)
 
 let int32_size = 4