[Dovecot] Encoding dovecot keywords

[Алексей Сундуков]

Hello.

If mailbox name include non latin chars, dovecot save it encode to
modification UTF-7. Example "тест" convert to "&BEIENQQ6BEEEQg-". If
replace & to + I can decode it:

<?php
$str = '+BEIENQQ6BEEEQg-';
echo iconv('UTF-7', 'UTF-8', $str);
?>


But I can't understand what encoding use dovecot for keywords? I set
"тест" (number 5) keyword:

cat dovecot-keywords
0 &bcienqrbbeiepgqybdaetw-_&bdwenqrcbdoema-
1 test
2 $label1
3 $label2
4 $label3
5 &beienqq6beeeqg-

but "&beienqq6beeeqg-" do not convert to "тест". Why?