[Users] Default headers in message view

[Paul]

On Tue, 15 Nov 2016 06:54:13 +0100
Manuel Groß <mgr at nordkrater.de> wrote: 

> FAQ, User manual, Wiki, Git repo. But maybe I'm just blind or
> something, that's why I'm asking for a pointer.

https://tools.ietf.org/html/rfc2822#section-3.6.3

Mostly the Bcc'ed recipient of a message will not even see the Bcc
header.

Several pertinent RFC documents can be found in Claws Mail git repo:
http://git.claws-mail.org/?p=claws.git;a=tree;f=doc/src;h=9fb55a720d39c44811000357b4297c56172afad5;hb=HEAD

with regards

Paul