I use an older version of WSFTP (8.0). I wanted to backup the .ini file that holds all the site configurations. I was unable to locate it, but eventually search enough and found it.
WS support says the path is:
Here is the path I needed to get the file.
C:\users\<username>\AppData\local\VirtualStore\Program Files(x86)\Common Files\Ipswitch\WS_FTP\Sites\WS_FTP.ini
I hope this helps someone.