The ckeditor5.api.php file contains a reference to a hook that is not invoked by Backdrop core

[avpaderno]

As noticed by @swampopus in #2054, ckeditor5.api.php lists hook_ckeditor5_settings_alter() as one of the invoked hooks, but that hook is not invoked by Backdrop core, which instead invokes hook_ckeditor5_config_alter(), in ckeditor5_get_config().

The ckeditor5.api.php file needs to be corrected to reference the correct hook (hook_ckeditor5_config_alter()).

[indigoxela]

Nice catch! 👍 The API documentation has just been copied over from CKE4 back then, but the actual alter hook has been renamed for CKE5.

But there's more... The structure of the array is also substantially different with CKE5, so the foreach from the API example is quite misleading.