add-slug-wocommerce-csv-export.php

<?php
/**
 * Add the custom column to the exporter and the exporter column menu.
 * 
 * @link https://github.com/woocommerce/woocommerce/wiki/Product-CSV-Importer-&-Exporter#adding-custom-export-columns-developers
 *
 * @param array $columns.
 * @return array $columns.
 */
function cameronjonesweb_add_export_columns( $columns ) {
	// column slug => column name.
	$columns['slug'] = 'Slug';
	return $columns;
}

add_filter( 'woocommerce_product_export_column_names', 'cameronjonesweb_add_export_columns' );
add_filter( 'woocommerce_product_export_product_default_columns', 'cameronjonesweb_add_export_columns' );

/**
 * Provide the data to be exported for one item in the column.
 * 
 * @link https://github.com/woocommerce/woocommerce/wiki/Product-CSV-Importer-&-Exporter#adding-custom-export-columns-developers
 *
 * @param mixed $value (default: '').
 * @param WC_Product $product.
 * @return mixed $value - Should be in a format that can be output into a text file (string, numeric, etc).
 */
function cameronjonesweb_export_column_slug( $value, $product ) {
	$value = get_post_field( 'post_name', $product->get_id() );
	return $value;
}
// Filter you want to hook into will be: 'woocommerce_product_export_product_column_{$column_slug}'.
add_filter( 'woocommerce_product_export_product_column_slug', 'cameronjonesweb_export_column_slug', 10, 2 );