I've been working on a browser extension to make Hacker News easier to use. No, not change the UX, but just some nice conveniences. Keyboard navigation, inline replies, dark mode, a nicer topcolors page, and many more features. I am hoping to add some social features, like being able to follow someone. All in a well-tested and extensible codebase that has minimal impact on the site. Open source, GPL...
Orange Juice
https://oj-hn.com