Meshviewer - more in the README

A simple, secure, and stealthy port knocking implementation that does not use libpcap or bind to a socket interface.

Create backups of an Android device over USB (requires adb and TWRP recovery)

Certbot is EFF's tool to obtain certs from Let's Encrypt and (optionally) auto-enable HTTPS on your server. It can also act as a client for any other CA that uses the ACME protocol.

The server/gateway confguration, scripts, examples etc.

The Firmware for the Freifunk Ulm Community

OpenKeychain is an OpenPGP implementation for Android.

Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)

A private messenger for Android.