diff --git a/Doc/c-api/concrete.rst b/Doc/c-api/concrete.rst
index 6799ca0..a2aaeea 100644
--- a/Doc/c-api/concrete.rst
+++ b/Doc/c-api/concrete.rst
@@ -585,6 +585,7 @@
 this section deals with the specific kinds of sequence objects that are
 intrinsic to the Python language.
 
+.. XXX sort out unicode, str, bytes and bytearray
 
 .. _stringobjects: