Rocket.Chat/app/ui-message/client/messageBox/messageBoxReplyPreview.html

<template name="messageBoxReplyPreview" args="input replyMessageData">
	<div class="reply-preview message-popup">
		<div class="message">
			{{> messageAttachment text=replyMessageData.msg author_name=replyMessageData.u.username}}
		</div>
		<div class="rc-message-box__icon cancel-reply" data-mid="{{replyMessageData._id}}">
			{{> icon block="rc-input__icon-svg" icon="cross"}}
		</div>
	</div>
</template>