Access to Page Revisions Link

/**
 * Implements hook_form_FORM_ID_alter() for node forms.
 */
function gin_gutenberg_plus_form_node_form_alter(&$form, FormStateInterface $form_state) {
  $node = $form_state->getFormObject()->getEntity();

  // Leave early if Gutenberg is not enabled for this entity.
  if ($node instanceof NodeInterface) {
    return;
  }

  $nid = $node->id();
  $form['actions']['revisions'] = [
    '#type' => 'link',
    '#title' => t('Revisions'),
    '#url' => \Drupal\Core\Url::fromRoute('entity.node.version_history', ['node' => $nid]),
    '#attributes' => [
      'class' => ['action-link'],
    ],
    '#weight' => -10,
  ];
}