diff --git a/lisp/textmodes/yaml-ts-mode.el b/lisp/textmodes/yaml-ts-mode.el
index dfa8d22fb34..43e8868fc44 100644
--- a/lisp/textmodes/yaml-ts-mode.el
+++ b/lisp/textmodes/yaml-ts-mode.el
@@ -2,10 +2,10 @@
 
 ;; Copyright (C) 2022-2023 Free Software Foundation, Inc.
 
-;; Author     : Randy Taylor <dev@rjt.dev>
-;; Maintainer : Randy Taylor <dev@rjt.dev>
-;; Created    : December 2022
-;; Keywords   : yaml languages tree-sitter
+;; Author: Randy Taylor <dev@rjt.dev>
+;; Maintainer: Randy Taylor <dev@rjt.dev>
+;; Created: December 2022
+;; Keywords: languages
 
 ;; This file is part of GNU Emacs.
 
@@ -23,15 +23,18 @@
 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
 
 ;;; Commentary:
-;;
+
+;; This file provides basic YAML syntax highlighting using Tree
+;; Sitter.  To use the `yaml-ts-mode' major mode you will have to make
+;; sure that you have installed the appropriate grammar.
 
 ;;; Code:
 
 (require 'treesit)
 
-(declare-function treesit-parser-create "treesit.c")
+;; (declare-function treesit-parser-create "treesit.c") ;doesn't appear necessary
 
-(defvar yaml-ts-mode--syntax-table
+(defvar yaml-ts-mode-syntax-table
   (let ((table (make-syntax-table)))
     (modify-syntax-entry ?#  "<"  table)
     (modify-syntax-entry ?\n ">"  table)
@@ -59,7 +62,8 @@ yaml-ts-mode--font-lock-settings
       (null_scalar)
       (reserved_directive)
       (tag_directive)
-      (yaml_directive)] @font-lock-constant-face)
+      (yaml_directive)]
+     @font-lock-constant-face)
 
    :language 'yaml
    :feature 'delimiter
@@ -83,7 +87,8 @@ yaml-ts-mode--font-lock-settings
    '([(block_scalar)
       (double_quote_scalar)
       (single_quote_scalar)
-      (string_scalar)] @font-lock-string-face)
+      (string_scalar)]
+     @font-lock-string-face)
 
    :language 'yaml
    :feature 'escape-sequence
@@ -120,10 +125,9 @@ yaml-ts-mode--font-lock-settings
 ;;;###autoload
 (define-derived-mode yaml-ts-mode text-mode "YAML"
   "Major mode for editing YAML, powered by tree-sitter."
-  :group 'yaml
-  :syntax-table yaml-ts-mode--syntax-table
+  ;; :group 'yaml ;; no such customisation group was defined?
 
-  (when (treesit-ready-p 'yaml)
+  (when (treesit-ready-p 'yaml)         ;why not raise an `user-error'?
     (treesit-parser-create 'yaml)
 
     ;; Comments.
@@ -143,9 +147,8 @@ yaml-ts-mode
 
     (treesit-major-mode-setup)))
 
-(if (treesit-ready-p 'yaml)
-    (add-to-list 'auto-mode-alist '("\\.ya?ml\\'" . yaml-ts-mode)))
+(when (treesit-ready-p 'yaml)
+  (add-to-list 'auto-mode-alist '("\\.ya?ml\\'" . yaml-ts-mode)))
 
 (provide 'yaml-ts-mode)
-
 ;;; yaml-ts-mode.el ends here