Question: I've looked at a lot of the git repositories, but I'm not sure which one to start with (and they're fairly large, so I want to avoid scanning 25 gig of data). Where would I find the code to handle CVS and Subversion integration?

Answer: 
You can browse all of the git repositories at <http://git.eclipse.org/c/> . The one you want is <http://git.eclipse.org/c/platform/eclipse.platform.team.git/> (cloning URLs are shown at the bottom).
Update 2022: as illustrated by [gitlab.eclipse.org/eclipsefdn/helpdesk issue 1100](https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/issues/1100), and [issue 915](https://gitlab.eclipse.org/eclipsefdn/helpdesk/-/issues/915), everything is in the process to be transferred to GitHub.

The old (2014-2021) [`git.eclipse.org/c/platform/eclipse.platform.team.git/`](http://git.eclipse.org/c/platform/eclipse.platform.team.git/) would therefore be soon (Q2 2022) be found under <https://github.com/eclipse-platform>.

<https://github.com/eclipse-platform/eclipse.platform.team>