This was was linked to, I think indirectly, a week or two ago. I asked the same thing there, and the reply I got was that it's required because it's a "beta" v

This was was linked to, I think indirectly, a week or two ago. I asked the same thing there, and the reply I got was that it's required because it's a "beta" version of the book and they want reviewers to open issues/pull requests when problems are found. It's an interesting idea, but there's no way I'm giving a stranger write access to my GitHub account.