In drupal 8, I have created a custom module to alter the user login and register forms in 2 class that extends
Whereas for the login form I can add some link in the
$form['action'] array or add a class to the submit button:
$form['actions']['submit']['#attributes'] = [ 'class' => ['btn', 'btn-primary'], ];
a contrario, there is no action array in user register
So how can I access in my class the submit button, and more generally, the action array?