What is nice about that page is that it points to https://github.com/eclipse
which contains a number of GitHub forks/clones of multiple eclipse repos. Same question here, shouldn't org.eclipse.e4.scripting be there?
I have to say that I have more experience in using GitHub than the current Eclipse foundation set-up, so my current plan (unless you can point me on a better direction) is to create a fork/clone of http://git.eclipse.org/c/e4/org.eclipse.e4.scripting.git
in GitHub and use it as a base for my changes/patches/fixes/branches.