Actually the answer is from http://josh.postach.io/multiple-file-upload-custom-dexterity-content-types-plone-5-02a
The following snippet works for me:
<fieldset tal:condition="context/files">
<legend>Attached Files</legend>
<ul>
<tal:files repeat="item context/files">
<li><a href=""
tal:attributes="href string:${context/absolute_url}/@@edit/++widget++form.widgets.files/@@download/${repeat/item/index}"
tal:content="item/filename">Attached File</a></li>
</tal:files>
</ul>
</fieldset>
Although using @@edit
is wired here, hopefully we will have better version of plone.formwidget.multifile or related packages soon.