user_user_view

user_user_view(array &$build, UserInterface $account, EntityViewDisplayInterface $display)

function user_user_view(array &$build, UserInterface $account, EntityViewDisplayInterface $display) {
  if ($display->getComponent('member_for')) {
    $build['member_for'] = array(
      '#type' => 'item',
      '#markup' => '<h4 class="label">' . t('Member for') . '</h4> ' . \Drupal::service('date.formatter')->formatTimeDiffSince($account->getCreatedTime()),
    );
  }
}