HN Keyboard Nav is a free Chrome extension developed by nick.script0. This handy tool enhances your browsing experience on the Hacker News comment threads by providing keyboard shortcuts and features that allow for efficient navigation and focus.

With HN Keyboard Nav, you can easily move through comment threads using simple keyboard shortcuts. Press 'j' to move to the next comment and 'k' to go to the previous comment. If you want to navigate within the same level of comments, you can use 'Shift+j' to move to the next same-level comment and 'Shift+k' to go to the previous same-level comment.

In addition to comment navigation, HN Keyboard Nav offers shortcuts for moving up and down comment levels. Use 'Shift+n' to move up a comment level forward and 'Shift+m' to move up a comment level backward. You can also quickly jump to root-level comments with 'n' for next root-level comment and 'm' for previous root-level comment.

To help you maintain context in deep threads, the extension allows you to show the current parent comment inline by holding the 'p' key. You can also hide or show the current comment and its children using the 'l' key.

Furthermore, HN Keyboard Nav provides options for highlighting important elements. By pressing 'h', you can highlight the username of the currently focused comment. Additionally, you can highlight selected text with the same 'h' key.

Another useful feature of this extension is the ability to add friends. You can permanently highlight a username with a note that persists on all pages by using the 'f' key.

Overall, HN Keyboard Nav is a valuable tool for Hacker News users who want to navigate comment threads efficiently and focus on the commenters they value. With its intuitive keyboard shortcuts and helpful features, this Chrome extension enhances the browsing experience on Hacker News.