New API for adding theme-specific styles in CKEditor 5
How to load stylesheets in CKEditor 5.
Resources
Upgrade coordination for modules providing CKEditor 4 plugins
Table of Ckeditor 5 module compatibility.
CKEditor 5 features overview
CKEditor 5 features.
Drupal Core CKEditor 5 Issues
Drupal Core issue queue for CKEditor 5.
Migration from CKEditor 4
Differences between 4 and 5.
Plugin compatibility table.
Tips
Configure CKEditor Toolbar Dropdown Menus
The CKEditor module allows placing separators and wrappers in the toolbar.
If there are no separators, they are automatically grouped when overflowing.
See the full options here: https://ckeditor.com/docs/ckeditor5/latest/getting-started/setup/toolbar.html
You can edit the config file and add dropdown menus using the advanced configuration format.