I was confused, too. From what I gather, this is to allow authors to control fullscreen mode from script. I don't think you deserved the downvote. The linked

I was confused, too. From what I gather, this is to allow authors to control fullscreen mode from script. I don't think you deserved the downvote. The linked article certainly could have afforded to be clearer. After a reread, I'm still not convinced that what they're trying to say is clear without some outside intuition.