diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 593dcb5..1003010 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -6382,6 +6382,9 @@
 					otherwise
 			wincol		leftmost screen column of the window;
 					"col" from |win_screenpos()|
+			textoff		number of columns occupied by any
+					'foldcolumn', 'signcolumn' and line
+					number in front of the text
 			winid		|window-ID|
 			winnr		window number
 			winrow		topmost screen line of the window;