diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index fb957e5..941c6a7 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 Mar 07
+*builtin.txt*	For Vim version 9.1.  Last change: 2024 Mar 12
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -10947,7 +10947,9 @@
 			#	the number of the last accessed window (where
 				|CTRL-W_p| goes to).  If there is no previous
 				window or it is in another tab page 0 is
-				returned.
+				returned.  May refer to the current window in
+				some cases (e.g. when evaluating 'statusline'
+				expressions).
 			{N}j	the number of the Nth window below the
 				current window (where |CTRL-W_j| goes to).
 			{N}k	the number of the Nth window above the current