To quote, roughly translated: CHANGELOG OPENPS3FTP 3.1 (OPS3PS3FT31.pkg)
Fixed data connections
Removed unnecessary checks.
Use O2 instead
Compatible with 4.46 LDZ FERROX/HABIB
Improved Speed Transfer
Fixed minor bug cfw 4.46
(may still have some bugs, please report.)
Update: From jjolano: OpenPS3FTP is an open source FTP server for the PlayStation 3. It supports the basic FTP commands that the typical user would need to transfer files in and out of their console. OpenPS3FTP is built using libraries from the PSL1GHT SDK (commit 534e589).
Release Candidate 4:
Minimizing use of string streams
Added more information in README.txt and ChangeLog.txt
Fixed a few errors and potential bugs from previous release candidates