What Hacker News Says is a Chrome extension developed by Pino Ceniccola. It falls under the category of Browsers and is specifically categorized as an Add-ons & Tools subcategory. This extension allows users to easily find Hacker News threads related to the webpage they are currently browsing.

The extension is dead-simple yet very useful. It utilizes the HN Search API powered by Algolia to fetch relevant threads from Hacker News. The extension only fetches the API when the user clicks on the extension's popup, ensuring privacy and avoiding unnecessary background scripts. Additionally, it requires minimum permissions, with just the "activeTab" permission.

Overall, What Hacker News Says is a handy Chrome extension that provides a convenient way to discover Hacker News threads related to the webpage you are browsing.