What is this magic mail client that shows BCC?

Question

Email

Just saw an interesting post

The password in the letter came in clear text and a hidden copy ( which not every client will show )

Many people are familiar with the common mistake of inexperienced representatives of "office plankton" who make mailings to extensive databases by including all recipients in TO or CC, as a result of which everyone can familiarize themselves with the entire list, or even reply to everyone. Once upon a time, my tasks included sending out price lists to partners, and I was completely sure that I was smarter than the aforementioned ones and scored the same list, only not in TO, but in BCC and thought that no one (the mailing list) would see it as a result. And then suddenly...

Answer 1

Did you read the comments on the post?
Perhaps the answer is already there?
habrahabr.ru/post/240233/#comment_8061807