From the  bbFTP Website:

bbFTP is a file transfer software. It implements its own transfer protocol, which is optimized for large files (larger than 2GB) and secure as it does not read the password in a file and encrypts the connection information.

BbFTP also provides well documented security hooks for customising authentication and authorisation. This feature was a key reason for selecting bbFTP as the file transfer layer for NDG.

There is a bbFTP mailing list with archives available  here. This appears to be an extremely low volume list (only a couple of emails a quarter).

The imported bbFTP-3.2.0 sources are available as a seperate SVN branch at TI05-delivery/branches/vendor/.