silverstripe-userforms/code/model/recipients/UserFormRecipientEmail.php

<?php


/**
 * Email that gets sent to the people listed in the Email Recipients when a
 * submission is made.
 *
 * @package userforms
 */

class UserFormRecipientEmail extends Email
{

    protected $ss_template = "SubmittedFormEmail";

    protected $data;

    public function __construct($submittedFields = null)
    {
        parent::__construct($submittedFields = null);
    }

    /**
     * Set the "Reply-To" header with an email address rather than append as
     * {@link Email::replyTo} does.
     *
     * @param string $email The email address to set the "Reply-To" header to
     */
    public function setReplyTo($email)
    {
        $this->customHeaders['Reply-To'] = $email;
    }
}