HN's semantic markup isn't always great, but in this case it simply uses <pre> styled with overflow: auto.
> The behavior of the 'auto' value is user agent-dependent, but should cause a scrolling mechanism to be provided for overflowing boxes. — http://www.w3.org/TR/CSS2/visufx.html#overflow
Apple's rendering is overly pretty to the point of being useless. They dropped support for a perfectly reasonable semantic requirement (make all the content available) which was in the spec literally before their browser existed.
> The behavior of the 'auto' value is user agent-dependent, but should cause a scrolling mechanism to be provided for overflowing boxes. — http://www.w3.org/TR/CSS2/visufx.html#overflow
Apple's rendering is overly pretty to the point of being useless. They dropped support for a perfectly reasonable semantic requirement (make all the content available) which was in the spec literally before their browser existed.