The OpenCV developer site

OpenCV is an open source project that welcomes user contributions. You can access the developer site at https://docs.opencv.org/. Among other things, you can access the currently developed version of OpenCV. The community uses Git as its version control system. You then have to use it to check out the latest version of OpenCV. Git is also a free and open source software system; it is probably the best tool you can use to manage your own source code. You can download it from https://git-scm.com/.