How to add a description to the node title field in form

Question

In my Drupal 8 project I tried to find a way to add a description to the title field of a node form by hook_form_alter. Following code(s) did not lead to success:

$form['title']['widget'][0]['#description'] =  \Drupal\Core\Field\FieldFilteredMarkup::create('hallo');
$form['title']['widget']['#description'] =  \Drupal\Core\Field\FieldFilteredMarkup::create('hallo');
$form['title']['#description'] =  \Drupal\Core\Field\FieldFilteredMarkup::create('hallo');

What is the correct place to define a description for the node title field?

Answer 1

After several trial and errors this is the code working:

$form['title']['widget'][0]['value']['#description'] =  \Drupal\Core\Field\FieldFilteredMarkup::create('hallo');