Bug#1009181: File suffix for message mbox links should be .eml

On 10/04/2022 03:54, Don Armstrong wrote:
> 
> The only real difference between a single message in an mbox and a
> complete mbox is From escaping.

I had an impression that MUA may decode messages from 7-bit transfer 
encoding including quoted-printable and base64 fragments in headers 
before saving .eml files. I rarely use .eml files, so I may be wrong, 
and I do ask for such transformation from debbugs.

> Frankly, using the extension to determine mime time is bad practice, but
> it's a common bad practice.

In this particular case even libmagick is not a rescue, both 
application/mbox and message/rfc866 are detected as text/plain. Though 
my opinion is that thunderbird should have some option to make intention 
clear.