xmpp.chapril.org-conversejs/src/templates/message.html

<div class="chat-message {{extra_classes}}" data-isodate="{{isodate}}" data-msgid="{{msgid}}">
    <span class="chat-msg-{{sender}}">{{time}} {{username}}:&nbsp;</span>
    <span class="chat-msg-content">{{message}}</span>
</div>