GitHub announced today that the editor it has been working on is now open source.
Today, we're excited to announce that we are open-sourcing Atom under the MIT License. We see Atom as a perfect complement to GitHub's primary mission of building better software by working together. Atom is a long-term investment, and GitHub will continue to support its development with a dedicated team going forward. But we also know that we can't achieve our vision for Atom alone. As Emacs and Vim have demonstrated over the past three decades, if you want to build a thriving, long-lasting community around a text editor, it has to be open source.
I have been using the Atom beta as my primary editor for the past few weeks and have been very happy with it.
It is currently only available for the mac, but it is based on Chromium and Node, and "Windows and Linux releases are on the roadmap."
(Score: 3, Informative) by xlefay on Thursday May 08 2014, @01:45AM
Actually, the OP was wrong, it is in fact available for Linux and Windows they just don't advertise it on the atom's website.
Source: Atom's readme file: https://github.com/atom/atom#linux-requirements [github.com] & myself, since I've been testing it too.