Which repo is the repo I should be reaping from?

[Rick Coleman]

Hi all,

I was reading the last post, subject:
"[GitHub] [ctakes] Haags commented on issue #8: Issue clean install 
using maven for ctakes-ytex"

and that got me wondering, the download page mentions Subversion, but 
there's a GitHub.

Which repository is the *definitive* repository?  Why are there two on 
two different systems?

Thanks,

rik.