This is an old emacs package that I needed as a dependency of another package (https://github.com/knu/elscreen), and the old links were dead. I got my hands on it and though others might need it too, so here it is.
the original documentation on emacswiki says it supports emacs 18-20, but at the time of this writing I am using emacs 24.2.1 and it is working. FWIW.