This document presents a header field which will provide an
identifier for an e-mail distribution list. This header SHOULD be
included on all messages distributed by the list (including command
responses to individual users), and on other messages where the
message clearly applies to this particular distinct list.
However, in my testing, I do not see this header being added to distribution lists that I configure in Zimbra (using ZCS OSE 8.7.1). How can I enable adding of this important header field to my distribution lists? Thanks!