It's always been open-source, at least according to its author's blog post, which was previously discussed here: https://news.ycombinator.com/item?id=10573561 h

It's always been open-source, at least according to its author's blog post, which was previously discussed here: https://news.ycombinator.com/item?id=10573561 https://news.ycombinator.com/item?id=10573561