I'm trying to find out what password hash postfixadmin is using. I need to ensure that postfix, postfixadmin and roundcube all have the same password hash so I can use a few password plugins in roundcube.
look in your PFA "config.inc.php" or "config.local.php" for the line that reads something like this
$CONF = 'md5crypt';
If you are using the config.local.php, which is probably recommended, then the setting in this file is the one that will be in use.