> I can't understand why they would preclude Atom from running in a browser.

If memory serves me right, I believe it was conceived to be a standalone commercial product, with tight GitHub integration; but somewhere a long the line, it became a free open source project that it is today.

I still don't understand why so much effort is being put into an editor though. I'm guessing people are drawing a comparison with the web browser war, with who owns the editor, will own the developer mind share.