It's also probably one of the oldest open source repositories. OpenBSD pretty much pioneered the concept of making their VCS open to the public over the Internet (hence the name).

Yes, OpenBSD invented anonymous CVS which was the first way to access a version control system without prior authorization http://www.openbsd.org/papers/anoncvs-paper.pdf

It was already ubiquitous in 1997 when I got started working on open source software, so I took it for granted. I was surprised to find out 20 years later how new anoncvs had been and how fast it spread to other projects like FreeBSD and Apache httpd.