diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 040780b355..bc833b11fc 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 9.1.  Last change: 2023 Dec 27
+*syntax.txt*	For Vim version 9.1.  Last change: 2024 Jan 03
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -1261,7 +1261,7 @@ To highlight KDE-reserved features, set >
 g:desktop_enable_kde follows g:desktop_enable_nonstd if not supplied
 
 
-DIFF							*diff.vim*
+DIFF						*diff.vim* *ft-diff-syntax*
 
 The diff highlighting normally finds translated headers.  This can be slow if
 there are very long lines in the file.  To disable translations: >
@@ -1270,7 +1270,15 @@ there are very long lines in the file.  To disable translations: >
 
 Also see |diff-slow|.
 
+Since the Vim 9.1 release |version-9.1| the diff filetype links the diffAdded,
+diffRemoved and diffChanged highlighting groups to |hl-DiffAdd|,
+|hl-DiffDelete| and |hl-DiffChange| by default.  If you do not want this, you
+can change it to the previous groups like this in your |.vimrc| >
 
+	hi link diffRemoved Special
+	hi link diffChanged PreProc
+	hi link diffAdded Identifier
+<
 DIRCOLORS			       *dircolors.vim* *ft-dircolors-syntax*
 
 The dircolors utility highlighting definition has one option.  It exists to
diff --git a/runtime/doc/tags b/runtime/doc/tags
index 215e189847..e8ac2bc191 100644
--- a/runtime/doc/tags
+++ b/runtime/doc/tags
@@ -7207,6 +7207,7 @@ ft-cynlib-syntax	syntax.txt	/*ft-cynlib-syntax*
 ft-dart-syntax	syntax.txt	/*ft-dart-syntax*
 ft-dash-syntax	syntax.txt	/*ft-dash-syntax*
 ft-desktop-syntax	syntax.txt	/*ft-desktop-syntax*
+ft-diff-syntax	syntax.txt	/*ft-diff-syntax*
 ft-dircolors-syntax	syntax.txt	/*ft-dircolors-syntax*
 ft-docbk-syntax	syntax.txt	/*ft-docbk-syntax*
 ft-docbksgml-syntax	syntax.txt	/*ft-docbksgml-syntax*