Primitive FTPd is a free Android application developed by wolpi under the Utilities & Tools category. This program is a simple FTP server that enables file exchange with other machines over WiFi. With this app, users can easily transfer files without the need for USB cables. The app runs without root privileges and is not started when the device boots. Users can control when the server runs and prevent standby to avoid long uploads and downloads from aborting (configurable). Additionally, transfers can be encrypted by SFTP.

Overall, Primitive FTPd is a useful app for those who need to transfer files between their Android device and other machines over WiFi. The app is easy to use and offers encryption for secure file transfers. However, it lacks some advanced features such as the ability to run in the background or the ability to set up user accounts.