FileItem::mirrorDataEntityFields

static function mirrorDataEntityFields(): array
{
	$additionalFields = [
		'SUBTYPE' => [
			'field' => 'subtype',
			'set' => 'setSubtype', /** @see FileItem::setSubtype */
			'get' => 'getSubtype', /** @see FileItem::getSubtype */
			'beforeSave' => 'validateSubtype', /** @see FileItem::validateSubtype */
		]
	];

	return array_merge(parent::mirrorDataEntityFields(), $additionalFields);
}