1 files changed, 3 insertions, 1 deletions

diff --git a/src/macros.c b/src/macros.c
index d0219a3be04..09ae87b0a59 100644
--- a/src/macros.c
+++ b/src/macros.c
@@ -392,7 +392,9 @@ syms_of_macros ()
   defsubr (&Sstore_kbd_macro_event);
 
   DEFVAR_KBOARD ("defining-kbd-macro", defining_kbd_macro,
-                 doc: /* Non-nil while a keyboard macro is being defined.  Don't set this!  */);
+                 doc: /* Non-nil while a keyboard macro is being defined.  Don't set this!
+The value is the symbol `append' while appending to the definition of
+an existing macro.  */);
 
   DEFVAR_LISP ("executing-macro", &Vexecuting_macro,
                doc: /* Currently executing keyboard macro (string or vector); nil if none executing.  */);