use strict;
use warnings;
use Mail::Audit;
use MIME::Words qw(decode_mimewords);
use Encode;

open my $out, '>:utf8', "/some/file.txt";
my $mail = new Mail::Audit;
my $subj = $mail->get('Subject');
$subj = decode_utf8 decode_mimewords($subj);
print $out "$subj\n";

##</code><code>##

Subject: =?UTF-8?B?0KDRg9GB0YHQutC40Lk=?=

##</code><code>##

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