Take TabooHeaders, for example. Aptly named, this hidden option masterfully combines the best qualities of all three examples — and it is very useful, too. Using TabooHeaders, you can tell Eudora which header lines to hide when displaying a message.
You can hide all X- headers (which are less "standard" than the Subject: or From: headers and may include things like spam scores or virus scanner messages), for example, by making "x-" a taboo header. Adding "Rec" lets you hide all the "Received:" lines that are interesting but usually unnecessary to see.
Configure the Header Lines Displayed in Eudora
To configure the header lines displayed in Eudora:
- Edit the X-Eudora-option TabooHeaders.
- Add any headers you do not want to see displayed in messages by default.
- Separate entries with commas.
- Eudora hides all header lines that begin with an entry under TabooHeaders. Having "X-UIDL" in TabooHeaders will hide only lines beginning with "X-UIDL" while adding "X-" will hide "X-UIDL" as well as "X-MimeOLE" and any other header line beginning with "X-".
TabooHeaders has a default value of "X-UID, Received, Status, X-UIDL, Message, In-Reply, X-Priority, Mime-Version, Content, X-Persona, Resent-Message, References, Return, X400, X-400, Mail-System, Errors-To, X-List, Delivery, Disposition,X-Juno, Precedence, X-Attachments, X-MSMail, X-MimeOLE, X-Nav", which you can add to your custom headers.
The selection of headers to display on screen also affects which header lines are printed by Eudora.

