Who does develop the R core and libs, and how / where is it hosted?

Hello,

I saw Binaries, stable release-souzrces and daily snapshots of R, but
not something like a repository, visible for the public (like on githb for example).

How is the R development handled, what repositories / source code versioning tools
are used, who are the developers?

And is there something like a plan with future goals,
which are planned for the next releases?

Are there areas, where help is needed?
And in which way could support be done?


Ciao,
   Oliver