http://3cbzkrvakrpetjjppdwzbzqrlkmzatjs7jbyazap5gwutj32gcltjpqd.onion
Each has its own culture, written and unwritten rules, development process, documented requirements (which may be outdated) and more. Starting with a tiny contribution, even just a typo fix, is a good way to validate how code submissions, reviews and approvals work in a particular project.