8 – How to disable the advanced content filter for the tag?

If I add a label like on the source code side of CKEditor, it appears well on the WYSIWYG side. But if I go back to the source side and go back to the WYSIWYG side, it has been transformed as:


So, I tried to disable Advanced content filter when unchecking "Limit the allowed HTML tags and correct the defective HTML code" and also using the hook_ckeditor_plugin_info_alter, according to this answer.

I also tried to add allowedContent = true using ckeditor_config.

Unfortunately without any results.

How to disable this filtering, at least for