You can define your own FTP reply messages here.
If you think that built-in messages are too cryptic for your users or want to translate them, you can define them by yourself.
This page will allow you to set new FTP messages. You can also use server variables here.
For example, the default message for "Change Directory" is: CWD command successful. "%Dir" is current directory.
Here "%Dir" is a server variable. You can see a list of all the server variables at "Advance->Server Variables".