Source repo is https://github.com/booksbyus/scalable-c, pull requests are welcome.
Cover font: Kontrapunkt by Bo Linnemann, Kontrapunkt A/S. Text fonts: EB Garamond by Georg Duffner, MonospaceTypewriter by Manfred Klein..
Pieter Hintjens has been programming C since 1985. He is the author of many free software products written in C: Libero (1991), SFL (1996), Xitami (1998), OpenAMQ (2004). In 2007 he founded the ZeroMQ community. His github profile is https://github.com/hintjens.