drupal/core/modules/system/templates/datetime-form.html.twig

{#
/**
 * @file
 * Default theme implementation of a datetime form element.
 *
 * Available variables:
 * - attributes: HTML attributes for the datetime form element.
 * - content: The datelist form element to be output.
 *
 * @see template_preprocess_datetime_form()
 *
 * @ingroup themeable
 */
#}
<div{{ attributes.addClass('container-inline') }}>
  {{ content }}
</div>