"self-published open-source book for learning to code. Despite the lack of any initial audience, it topped GitHub trending charts worldwide during its launch. This is the story of this unexpected success." See the following link:
https://medium.freecodecamp.org/taking-off-the-successful-launch-of-an-open-source-book-7553a2262898
"Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency." : https://git-scm.com/