What does it do exactly?
Displays a Hacker News icon on your browser that changes color when the top story changes.
How does it do it?
The extension opens a websocket connection to the Hacker News Firebase (https://hacker-news.firebaseio.com/) so it can detect new top stories in real time.
Source code at https://github.com/robbiewain/hack-the-news
I really just made it for myself but others have found it useful so I'm posting here. Enjoy!