rtl_433 (despite the name) is a generic data receiver, mainly for the 433.92 MHz, 868 MHz (SRD), 315 MHz, 345 MHz, and 915 MHz ISM bands.

GrapheneOS is a privacy and security focused mobile OS with Android app compatibility developed as a non-profit open source project. It's focused on the research and development of privacy and security technology including substantial improvements to sandboxing, exploit mitigations and the permission model.

Found on https://ambrevar.xyz/blog-architecture/index.html

DECODER stands for DEveloper COmpanion for Documented and annotatEd code Reference. The project participants develop an open source Integrated Development Environment dedicated to improve the efficiency of software development and maintenance and the quality of software in medium criticality systems, such as in IoT, cloud computing and HPC.

Another blog using org-mode. Recommends https://ambrevar.xyz/blog-architecture/index.html but that produces a 404 error as of 2023-05-12.

Fileworthy is intended to facilitate easy management of files and notes across many devices.

Found on https://input.club/links/ via http://kiibohd.com/
See https://deskthority.net/wiki/Sun_Type_5

QMK (Quantum Mechanical Keyboard) is an open source community centered around developing computer input devices. The community encompasses all sorts of input devices, such as keyboards, mice, and MIDI devices. A core group of collaborators maintains QMK Firmware, QMK Configurator, QMK Toolbox, qmk.fm, and this documentation with the help of community members like you.
See also https://github.com/mihaiolteanu/mugur, an Emacs program to help configuring a QMK keyboard.

See also https://zee-nix.blogspot.com/2017/05/introducing-gps-share.html and https://github.com/zeenix/gps-share
gps-share is a utility to share your GPS device on local network. It has two goals:

Share your GPS device on the local network so that all machines in your home or office can make use of it.
Enable support for standalone (i-e not part of a cellular modem) GPS devices in Geoclue. Since Geoclue has been able to make use of network NMEA sources since 2015, gps-share works out of the box with Geoclue.

The latter means that it is a replacement for GPSD and Gypsy. While "why not GPSD?" has already been documented, Gypsy has been unmaintained for many years now. I did not feel like reviving a dead project and I really wanted to code in Rust language so I decided to create gps-share.