The extension collects nothing and has no analytics. Settings, bookmarks, your recently viewed stories and which comments you have seen are stored only in your browser (storage.local). It runs only on news.ycombinator.com. The only requests it makes are to Hacker News itself: the inline reply form and post go to news.ycombinator.com with your own session, exactly as HN's reply form does, and the username card asks Hacker News's public API (hacker-news.firebaseio.com) for that user's public profile, so that user name is sent to Hacker News when you hover it. Search and the "search HN" action are plain links to hn.algolia.com that you click yourself.