[NANOPASS]

Sorry, it was my lack of explanation.
I created an item of birth date the setting of Profile Fields

standard display of birthdate has become a DD-MM-YY.
I want to change to YY-MM-DD this

[NANOPASS]

Hi danbp
It Seems to me the answer to my question
But, the problem is not resolved.
I am very troubled!

plugins/buddypress/bp-xprofile/bp-xprofiles-class.php(bp-xprofile-classes.php):1459

	/**
	 * Constructor for the datebox field type
	 *
	 * @since BuddyPress (2.0.0)
 	 */
	public function __construct() {
		parent::__construct();

		$this->category = _x( 'Single Fields', 'xprofile field type category', 'buddypress' );
		$this->name     = _x( 'Date Selector', 'xprofile field type', 'buddypress' );

		$this->set_format( '/^\d{4}-\d{1,2}-\d{1,2} 00:00:00$/', 'replace' );  // "Y-m-d 00:00:00"
		do_action( 'bp_xprofile_field_type_datebox', $this );
	}

	/**
	 * Output the edit field HTML for this field type.
	 *
	 * Must be used inside the {@link bp_profile_fields()} template loop.
	 *
	 * @param array $raw_properties Optional key/value array of {@link http://dev.w3.org/html5/markup/input.html permitted attributes} that you want to add.
	 * @since BuddyPress (2.0.0)
	 */
	public function edit_field_html( array $raw_properties = array() ) {
		$user_id = bp_displayed_user_id();

		// user_id is a special optional parameter that we pass to {@link bp_the_profile_field_options()}.
		if ( isset( $raw_properties['user_id'] ) ) {
			$user_id = (int) $raw_properties['user_id'];
			unset( $raw_properties['user_id'] );
		}

		$year_html = $this->get_edit_field_html_elements( array_merge(
			array(
				'id'   => bp_get_the_profile_field_input_name() . '_year',
				'name' => bp_get_the_profile_field_input_name() . '_year',
			),
			$raw_properties
		) );

		$month_html = $this->get_edit_field_html_elements( array_merge(
			array(
				'id'   => bp_get_the_profile_field_input_name() . '_month',
				'name' => bp_get_the_profile_field_input_name() . '_month',
			),
			$raw_properties
		) );

Please tell me Where Do I change specifically.