Change exclusion for specific products in Google Product Feed

functions.php

<?php

function lw_gpf_exclude_product($excluded, $product_id, $feed_format) {
    // Do not exclude any of the specified product IDs.
    if ( in_array( $product_id, [ 28 ] ) ) {
        return false;
    }
    // Standard behaviour for all other products.
    return $excluded;
}
add_filter( 'woocommerce_gpf_exclude_product', 'lw_gpf_exclude_product', 11, 3);