Tor is a network of servers operated by volunteers. It allows users of these servers to improve their privacy and security while surfing on the Internet. You and your friends are able to access your FreedomBox via Tor network without revealing its IP address. Activating Tor application on your FreedomBox, you will be able to offer remote services (chat, wiki, file sharing, etc...) without showing your location. This application will give you a better protection than a public web server because you will be less exposed to intrusive people on the web.
=> the Onion Service .onion address
> Copy the entire address (ending in .onion) and paste it into the Tor Browser's address field, and you should be able to access your FreedomBox. (You may see a certificate warning because FreedomBox has a self-signed certificate.)