FreeBSD has three main source code repositories.
The "src" repository is used for the system sources, including both kernel and userland. The official repository is viewable here. A read-only mirror suitable for Summer of Code projects is available on GitHub.
The "ports" repository contains the ports tree and related build infrastructure. The official repository is viewable here. Here is the GitHub mirror.
"doc" hosts all of our documentation and website content. It is managed using Git and a mirror is available.
For Summer of Code, students can fork the appropriate FreeBSD repository on github or other free hosting services as approved by their mentor. Privately hosted repositories are not allowed by the program.
If your work is included in any of the FreeBSD repositories or upstreamed to other projects, please consider giving recognition to the GSoC program by adding the line below to your commit logs.
Sponsored by: Google, Inc. (GSoC 20xx)