diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index f1256b0..b117bf8 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -1,4 +1,4 @@
-*builtin.txt*	For Vim version 9.1.  Last change: 2024 Feb 21
+*builtin.txt*	For Vim version 9.1.  Last change: 2024 Feb 22
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4300,6 +4300,8 @@
 		  |visual-mode|, an empty list is returned.
 		- If {pos1}, {pos2} or {type} is an invalid string, an empty
 		  list is returned.
+		- If {pos1} or {pos2} is a mark in different buffer, an empty
+		  list is returned.
 
 		Examples: >
 			:xnoremap <CR>