Source editing mode doesn't show up (to edit HTML, not WYSIWYG)
I'm unable to edit HTML source code of my newsletter template with CKEditor 5, which worked well with CKEditor 4. There is no button to switch into source editing mode as shown here: https://ckeditor.com/docs/ckeditor5/latest/features/source-editing.html
This is mine:
What do I miss out? Maybe this is just a misconfiguration? (if so: maybe we should add the proper way into the documentation?)
My system: CiviCRM 5.67.0 on WordPress 6.4.1 with PHP 8.1.25. Thx :)