Dead link on, where are the std lib docs?

At the link to stdlib-doc project
is dead…

I am about to build ruby from src. One of my goals is to get the latest
stdlib docs, and to add to them (I think the docs for Time and Date are
missing some details that I’ve found by experimentation, I’d like to add
to the docs so that experimentation isn’t necessary).

Any suggestions on where to get started? Should I be building the 1.8
src, and submitting patches against it?