Zoho Mail user logged on the Web browser platform, by default, when user reply to an e-mail message, the indented original message is included in the message body. In quoted the original message has the typical message header as below:

---- On Sun, 12 Feb 2017 19:46:28 -0700 John.doe@zoho.com  wrote ----

I think that the message header (single-line format) summary is not friendly / comprehensive.
My suggestion is that it design "multi-line format" message headeras follows:

From: "John Doe" <john.doe@zoho.com>
Date: Sun, 12 Feb 2017 19:46:28 -0700
To: "Kate Lee" <klee@zohu.com>
Cc: (If the Original message has Cc address)
Subject: The subject
Priority: (If the Original message set a High or Low priority)

This will help the recipients or Cc addressee of the replied messages are easy to read the quoted Original message information, e.g. user can view the Cc addressee of quoted original message.