[hyperpape]

Certainly there's nothing in FOSS that mandates source control, but source control is one of the most important technologies discovered for developing software, and I'd be hard pressed to imagine a justification for relying on software that didn't use it.

[bandrami]

I'm showing my age here, but making version control public is a relatively recent thing; I can't think of a project before OpenBSD that did it, and it wasn't until SourceForge that the idea of projects just having source repos out there and visible became a popular idea, and that was like '99 or 2000. Most projects would just release tarballs and have a CVS repo that was limited to "approved" developers. And that was well after all the big distro build systems developed.

[Kwpolska]

It is likely that the `xpdf` project is developed under source control, but they don’t make the repository public. SQLite makes their repository public, but they do not accept contributions.