Hm, could you say why you think that? Looking at the github history it's hard to tell. The earliest history I can find for this page is from 2013[0], but it seems to be pretty clearly a transition and not the original writing of it. However, it's the only thing I can find in terms of aging the document.

[0]: https://github.com/janestreet/janestreet.github.com/commit/7...