diff --git a/runtime/doc/cmdline.txt b/runtime/doc/cmdline.txt
index cd38e90..989bd25 100644
--- a/runtime/doc/cmdline.txt
+++ b/runtime/doc/cmdline.txt
@@ -830,6 +830,11 @@
 Note: these are typed literally, they are not special keys!
 	<cword>    is replaced with the word under the cursor (like |star|)
 	<cWORD>    is replaced with the WORD under the cursor (see |WORD|)
+	<cexpr>    is replaced with the word under the cursor, including more
+		   to form a C expression.  E.g., when the cursor is on "arg"
+		   of "ptr->arg" then the result is "ptr->arg"; when the
+		   cursor is on "]" of "list[idx]" then the result is
+		   "list[idx]".  This is used for |v:beval_text|.
 	<cfile>    is replaced with the path name under the cursor (like what
 		   |gf| uses)
 	<afile>    When executing autocommands, is replaced with the file name