for some reasons, for example firmware updatse of IoT devices you need a readonly/anonymous FTP server and you don’t wont install and configure a whole ftp solution for this.
The python module twisted offers such a simple server. The ftp server must started with root privileges because it uses a port <1024. I always create a virtual python environment (ftp-venv) for such things.
Continue reading FTP: Setup a simple (read only) FTP server without install everything