diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 83e00e0..99e6d54 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.1.  Last change: 2025 Apr 13
+*options.txt*	For Vim version 9.1.  Last change: 2025 Apr 14
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -2085,6 +2085,28 @@
 		|i_CTRL-X_CTRL-D|
 	]	tag completion
 	t	same as "]"
+	f{func}	call the function {func}. Multiple "f" flags may be specified.
+		Refer to |complete-functions| for details on how the function
+		is invoked and what it should return.  The value can be the
+		name of a function or a |Funcref|.  For |Funcref| values,
+		spaces must be escaped with a backslash ('\'), and commas with
+		double backslashes ('\\') (see |option-backslash|).
+		If the Dict returned by the {func} includes {"refresh": "always"},
+		the function will be invoked again whenever the leading text
+		changes.
+		Completion matches are always inserted at the keyword
+		boundary, regardless of the column returned by {func} when
+		a:findstart is 1.  This ensures compatibility with other
+		completion sources.
+		To make further modifications to the inserted text, {func}
+		can make use of |CompleteDonePre|.
+		If generating matches is potentially slow, |complete_check()|
+		should be used to avoid blocking and preserve editor
+		responsiveness.
+	f	equivalent to using "f{func}", where the function is taken from
+		the 'completefunc' option.
+	o	equivalent to using "f{func}", where the function is taken from
+		the 'omnifunc' option.
 
 	Unloaded buffers are not loaded, thus their autocmds |:autocmd| are
 	not executed, this may lead to unexpected completions from some files