Source

File: wp-admin/includes/template.php

function page_template_dropdown( $default = '', $post_type = 'page' ) {
	$templates = get_page_templates( null, $post_type );

	ksort( $templates );

	foreach ( array_keys( $templates ) as $template ) {
		$selected = selected( $default, $templates[ $template ], false );
		echo "\n\t<option value='" . esc_attr( $templates[ $template ] ) . "' $selected>" . esc_html( $template ) . '</option>';
	}
}