This is in the FAQ at https://news.ycombinator.com/newsfaq.html and there's more explanation here:
https://news.ycombinator.com/item?id=10178989
https://hn.algolia.com/?sort=byDate&dateRange=all&type=comme...
We detached this subthread from https://news.ycombinator.com/item?id=19041410 and marked it off-topic.