Guys, sorry for my mistake. Xml backup contains encrypted passwords. They are encrypted with server's key. Correct answer is using /usr/local/psa/admin/bin/mail_auth_view utility. For example:
mysql> select mail_name,name,password from mail left join domains on mail.dom_id = domains.id inner join accounts where mail.account_id = accounts.id and postbox='true' order by name asc, mail_name asc;
+-----------+------------+----------------------------------------------------------------+
| mail_name | name | password |
+-----------+------------+----------------------------------------------------------------+
| rt | tttest.gov | $AES-128-CBC$f9qDGZ0SZqJv3yoUd8pMSA==$uoVzaIWEz/dDyy6Nglf7mw== |
+-----------+------------+----------------------------------------------------------------+
1 row in set (0.00 sec)
# /usr/local/psa/admin/bin/mail_auth_view
Authentication database contents:
+--------------------------------------+-----+--------------------------------------+
| address |flags| password |
+--------------------------------------+-----+--------------------------------------+
|
rt@tttest.gov | | vbn321 |
+--------------------------------------+-----+--------------------------------------+
Flags
A - account disabled
D - domain disabled
E - password encrypted