I fond an old discussion archived here, that come from Wikipedia, and that reproduces a private mail, without the consent of the author. How to erase it, or at least, hide/anonymize the name of the author ?
I don't know where "here" is and am surprised to learn that Wikipedia includes private email addresses. Perhaps I misunderstand you.
The author of any post should be able to edit it (More > Edit post) to remove material that should not be appear on a Nabble forum. It is also possible for administrators of a forum to add an "Edit_all" permission for themselves. That provides an "Edit post" option for all messages, not just their own.
If it is against forum policy to publish email addresses then ask your forum administrator to take the appropriate action.
Just a Volunteer Nabble Helper - because the nice folk at Nabble have helped me!