This page describes the basics of OSTB. For more detail, go to the wiki (link above). To ask a question, post an Issue (also above).
OSTB is for anyone interested in working on TB in an open source manner. "Open source" means that you work in line with the Six Laws. The most important of these is that all data and ideas are freely shared, anyone may participate and there will be no patents. While OSTB has a current focus on the discovery and development of new medicines, it is intended as a platform for any TB-related research.
There is a basic Landing Page which imports activity, but which needs an update. Updates go to Twitter. All OSTB molecules are on the Master List. Github (what you're looking at) is used for discussion and for file sharing. Different parts of OSTB have different "repositories" or "repos", from the General (what you're looking at) to the specific (such as the repo for Series 1). Discussion takes place by posting, and replying to, Issues (link above). To contribute, get a Github account.
There is an old Google+ community that could be resurrected. There is an email address (opensourcetb@gmail.com) but email is discouraged because it is bilateral.