--- a/mercurial/help.py	Tue Nov 22 12:44:22 2022 +0100
+++ b/mercurial/help.py	Fri Nov 25 15:14:40 2022 +0100
@@ -907,7 +907,7 @@
             if missing_order:
                 ui.develwarn(
                     b'help categories missing from CATEGORY_ORDER: %s'
-                    % missing_order
+                    % stringutil.forcebytestr(missing_order)
                 )
 
             # List per category.
@@ -940,7 +940,7 @@
             if missing_order:
                 ui.develwarn(
                     b'help categories missing from TOPIC_CATEGORY_ORDER: %s'
-                    % missing_order
+                    % stringutil.forcebytestr(missing_order)
                 )
 
             # Output topics per category.