get_custom_header_markup()

Source

File: wp-includes/theme.php

function get_custom_header_markup() {
	if ( ! has_custom_header() && ! is_customize_preview() ) {
		return '';
	}

	return sprintf(
		'<div id="wp-custom-header" class="wp-custom-header">%s</div>',
		get_header_image_tag()
	);
}