Hacker News Comment Highlighter is a Chrome extension that aims to make it easier to keep track of unread comments in Hacker News threads. Developed by Jonathan Bergknoff, this extension is available for free and falls under the category of Browsers with a subcategory of Add-ons & Tools.

The main purpose of this extension is to highlight new comments in Hacker News threads that you have previously visited. It keeps track of the comments you have seen and then highlights the new ones when you return to the page. This feature is particularly useful for active threads where you want to quickly catch up on what's new without having to manually search for unread comments.

Overall, Hacker News Comment Highlighter is a helpful tool for Hacker News enthusiasts who want to easily identify and read new comments in active threads. Its simplicity and open source nature make it a valuable addition to the Chrome browser.