> Hmm... I don't think this is actually a secure approach, as by default X is not secure. I think the post is more about containing what the browser has access

> Hmm... I don't think this is actually a secure approach, as by default X is not secure. I think the post is more about containing what the browser has access to in terms of Unix permissions in the event of it being controlled maliciously. The attack vector of X11 is equally applicable with or without the steps in this post.