I've never worked somewhere that didn't have me sign some kind of broad NDA-esque clause saying I wouldn't share proprietary or non-public info for a certain period after release (imo, completely reasonably). This blog post is literally nothing BUT non-public proprietary info. Like the parent I'm really surprised the blog author feels comfortable sharing all this. Even if it ended up being technically legal, I have to imagine this kind of thing is extremely frowned upon.