alt Hacker NewsSee https://news.ycombinator.com/item?id=43162211 and the links back from there and let us know if you still have a question.
(p.s. @dang is pretty much a no-op - for more reliable message delivery you need to email [email protected] - see https://news.ycombinator.com/newsguidelines.html)
I feel like the "title" attribute should be updated to the new timestamp in such cases. The tooltip plus I believe assistive technology relies on the title attribute and it can be confusing.