Added fields to the link editing balloon should appear above submit/cancel buttons

Can you please provide steps to reproduce? Such sample code would be helpful to A) write a failing test, B) then fix it.

That way we can prevent this from ever regressing again!

I'm a little bit puzzled by your request (and the new state for the issue), since I provided steps to reproduce the problem with the original ticket, and included a link to the code which demonstrates the problem. Can you be more specific about what you're asking for? Other than substituting our module name for "hook" in the name of the function, and a renamed variable, our code is pretty much identical to the code I linked to in the hook's documentation.

/**
 * Implements hook_ckeditor5_plugin_info_alter().
 */
function ebms_core_ckeditor5_plugin_info_alter(array &$plugin_definitions): void {
  assert($plugin_definitions['ckeditor5_link'] instanceof CKEditor5PluginDefinition);
  $definition = $plugin_definitions['ckeditor5_link']->toArray();
  $definition['ckeditor5']['config']['link']['decorators'][] = [
    'mode' => 'manual',
    'label' => 'Open in a new tab',
    'defaultValue' => TRUE,
    'attributes' => [
      'target' => '_blank',
    ],
  ];
  $plugin_definitions['ckeditor5_link'] = new CKEditor5PluginDefinition($definition);
}

Here's a screen shot showing the position of the new field.

#4 was exactly what I was after — thanks!

(I just wanted concrete steps to reproduce!)

Clarifying title.

This does not happen on a clean install.

This is caused by https://www.drupal.org/project/editor_advanced_link → .