This site is offered by a small group of developers within the free software community. They offer under GPL or LGPL license some kernel and user mode device drivers, X11 drivers, and embedded systems hardware and software. They also offer courses on embedded Linux, Linux device drivers and Samba. You need to contact them for specifics on how you can get their code and access their courses.
Platform:not bound to any particular hardware platform ;License: GPL license, X11 license, LGPL license
References: https://www.gnudd.com/