Document in ckeditor5.api.php how to access the CKEditor 5 instance given a DOM element

Quoting code from ckeditor5.js:

    const editor = Drupal.CKEditor5Instances.get(
      element.getAttribute('data-ckeditor5-id'),
    );

Why is that not adequate?

I mean sure its adequate, its also trivial to recreate the old map with a single line of code. I just personally don't see how generating unique ID's using Math.random() is a particular useful "improvement", was this map intended to aid in migration from CKE4? In that case I find this scheme of generating random IDs strange, if that was not the intend behind the map, then what was the intention?

No idea!

But you can find out the same way I can: through git archeology of the commit history at https://www.drupal.org/project/ckeditor5 → !

Example for work today:

let id = $('#edit-container-body-value').attr('data-ckeditor5-id');
Drupal.CKEditor5Instances.get(id).setData(email_content);

you can create a utils like this:

const ckeditorInstanceByElement = (elementId) => {
  let id = $(elementId).attr('data-ckeditor5-id');
  return Drupal.CKEditor5Instances.get(id);
};

#7: yep! That's similar to what I wrote at #3. How about this: let's add this explicitly to the ckeditor5.api.php documentation for improving discoverability of this.