diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 949d82f..18f6a67 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -6803,6 +6803,8 @@
 	   "auto"   	only when there is a sign to display
 	   "no"	    	never
 	   "yes"    	always
+	   "number"	display signs in the 'number' column. If the number
+			column is not present, then behaves like 'auto'.
 
 
 			*'smartcase'* *'scs'* *'nosmartcase'* *'noscs'*