It's not parsed as a block of some kind. The standalone <br> is parsed as it should be, without surprises. The closing tag, however, is parsed as another <br> t

It's not parsed as a block of some kind. The standalone <br> is parsed as it should be, without surprises. The closing tag, however, is parsed as another <br> tag. This is usual HTML behaviour, though, and since HTML 5 thoroughly specified.