How does mutt know to automatically choose charset?

[Peng Yu]

On 2/12/21, Derek Martin <invalid at pizzashack.org> wrote:
> On Thu, Feb 04, 2021 at 08:42:31AM -0600, Peng Yu wrote:
>> mutt can adjust the charset based on the input. But it seems that
>> EmailMessage from python can not do this automatically. How does mutt
>> choose the charset automatically based on the content? Thanks.
>
> You pasted the answer:
>> Content-Type: text/plain; charset=us-ascii
> ...
>> Content-Type: text/plain; charset=utf-8

The above are just the output of mutt. My question is how mutt knows
what charset to use. By what function mutt scans the input to
determine the charset?

-- 
Regards,
Peng