Hi Clément, If read correctly, you answered about Gnus (debbugs.el):
>>> --8<---------------cut here---------------start------------->8--- >>> (with-current-buffer gnus-original-article-buffer >>> (message-fetch-field "Message-ID")) >>> --8<---------------cut here---------------end--------------->8--- [...] >>> May I add too, that you can add "Message-ID" in gnus-visible-headers. [...] > You add '%M' in gnus-summary-line-format. [...] > Yes it does provide a built-in access, as I showed you. Just search for > "Message-id" in `C-h v gnus-summary-line-format`. And my message was: What appears to me “difficult” is that most of the tools as Email client are poorly supporting Message-ID. Somehow, the reader will judge if Message-ID is smoothly supported. :-) Cheers, simon