TITLE: Examples of (Git) open math (texts) projects
QUESTION [17 upvotes]: I am an active part of a research project on the positive effects of open math projects on the community. With open math projects I have in mind a particular thing, namely a GIT project on mathematics in which everyone can contribute and the final result is a collaborative text about some part of mathematics. The obvious examples are The stacks project, The HoTT book, Open logic project. I would like to know other examples of this kind of project. I am specially interested in those projects that have already finished (succeeded).

REPLY [3 votes]: I have a github page for my lecture notes on exterior differential systems.
The final document, to date: Introduction to exterior differential systems.