social/mail_forward/static/src/xml/mail_forward.xml

<?xml version="1.0" encoding="UTF-8"?>

<!-- © 2014-2015 Grupo ESOC <www.grupoesoc.es>
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html). -->

<template>
    <t t-extend="mail.thread.message">
        <t t-jquery=".oe_msg_icons .oe_reply" t-operation="before">
            <span class="oe_forward">
                <a title="Forward" class="oe_e">*</a>
            </span>
        </t>
    </t>
</template>