Sometimes you want to send email or newsgroup posts with custom headers. For example, the Approved: header can be used to post to a restricted "Announce" newsgroup for a class, or you may want to mark your email with an "X-No-Arc: yes" header to prevent a mailing list archive from saving a copy.
The easy way to add a custom header to the Thunderbird email/newsgroup compose window is by adding a user.js file to your configuration directory ( .thunderbird/default//user.js ) with the following line in it:
user_pref("mail.compose.other.header", "Approved");
Hello.
I know this is an old post so I’m not sure anyone will read this question, but here goes: You explained how to add a custom x-header. Is it possible to assign a default value for that new x-header?
I’m afraid I don’t know the answer to that one…perhaps somebody else does.
Haven’t tried but should be like this
user_pref(“mail.identity.idN.headers”, “archive”);
user_pref(“mail.identity.idN.header.archive”, “X-No-Archive: yes”);
Have a look at http://kb.mozillazine.org/Custom_headers for more information