I bet you those are in minority. That's the first one I ever saw anyway. I don't think that's very relevant. For those garage projects I've been interested in I've always found the source code.

Why subversion? Well, that's simply because it was the version control system of choice by those who set up garage. It's not a bad choice. It could've been CVS or GIT, but why would it be an issue at all that it's subversion? Then you say 'Why only subversion' (my highlighting). You're not seriously suggesting that there should be _more_ than one version control system repository for the same source code? That's certainly not very usual..