Freemius - WP Markdown Editor, Exporting

functions.php

<?php
/**
 * When exporting using WP default export tool, use the
 * markdown version when exist.
 *
 * @author Vova Feldman
 *
 * @param string $content
 *
 * @return string
 */
function freemius_export_markdown_content( $content ) {
	if ( ! class_exists( 'WPCom_Markdown' ) ) {
		// WP Markdown isn't installed.
		return $content;
	}

	$post = get_post();

	if ( ! post_type_supports( $post->post_type, WPCom_Markdown::POST_TYPE_SUPPORT ) ) {
		// Post type doesn't support markdown.
		return $content;
	}

	return ! empty( $post->post_content_filtered ) ?
		$post->post_content_filtered :
		$content;
}

add_filter( 'the_content_export', 'freemius_export_markdown_content' );