I use a lot of open source, and so does my company, so this is a chance for me to give something back.
There are all sorts of libraries and tools here, from making QR codes, to constructing CO2 monitors from an ESP32. Circuit board designs in KiCad are also included.
This repository also contains software and circuit designs published free by Andrews & Arnold Ltd.
"RevK", the "AJK" logo, and the "aa" logo, are, however, trademarks.