Contrib 的全名应该是 Contribution. 意思是第三方提供的内容，不是软件开发者提供的。

Reference 1: The contrib directory contains scripts, images, and other helpful things which are not part of the core docker distribution. Please note that they could be out of date, since they do not receive the same attention as the rest of the repository. https://docs.djangoproject.com/en/dev/ref/contrib/

Reference 2: It’s pretty common for an open source project to have a “contrib” directory as part of its project structure. This contains useful code donated to the project by outsiders. http://blog.startifact.com/posts/against-contrib.html