getRevisionIds example

$languages = $node->getTranslationLanguages();
    $has_translations = (count($languages) > 1);
    $node_storage = $this->entityTypeManager()->getStorage('node');

    $build['#title'] = $has_translations ? $this->t('@langname revisions for %title', ['@langname' => $langname, '%title' => $node->label()]) : $this->t('Revisions for %title', ['%title' => $node->label()]);
    $header = [$this->t('Revision'), $this->t('Operations')];

    $rows = [];
    $default_revision = $node->getRevisionId();
    $current_revision_displayed = FALSE;

    foreach ($this->getRevisionIds($node, $node_storage) as $vid) {
      /** @var \Drupal\node\NodeInterface $revision */
      $revision = $node_storage->loadRevision($vid);
      // Only show revisions that are affected by the language that is being       // displayed.       if ($revision->hasTranslation($langcode) && $revision->getTranslation($langcode)->isRevisionTranslationAffected()) {
        $username = [
          '#theme' => 'username',
          '#account' => $revision->getRevisionUser(),
        ];

        // Use revision link to link to revisions that are not active.