diff --git a/runtime/doc/helphelp.txt b/runtime/doc/helphelp.txt
index c49a4d5..f3c5293 100644
--- a/runtime/doc/helphelp.txt
+++ b/runtime/doc/helphelp.txt
@@ -1,4 +1,4 @@
-*helphelp.txt*	For Vim version 9.1.  Last change: 2025 Jun 03
+*helphelp.txt*	For Vim version 9.1.  Last change: 2025 Jul 07
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -410,6 +410,24 @@
 in such a modeline, that can have undesired consequences.
 
 
+STYLE
+
+If your Vim has 'modeline' enabled, Vim should follow the preferred style
+automatically when editing built-in help files.
+
+Vim help files should be formatted for a 'textwidth' of 78 characters, so they
+look good in a typical 80 x 24 terminal window.
+
+Use two spaces between the final dot of a sentence of the first letter of the
+next sentence.  Like this.
+
+Use tab characters for aligning content, with a 'tabstop' setting of 8.
+This also helps reduce the file size.
+
+Always use |:retab| after you have finished editing.  Don't blindly use
+|:retab!|, always review what will be changed to avoid unwanted changes.
+
+
 TAGS
 
 To define a help tag, place the name between asterisks ("*tag-name*").  The