Bookmark 301 Updater is a free Chrome add-on developed by fredden that helps you automatically update bookmarks for permanently moved resources while browsing. This useful tool ensures that your bookmarks stay up to date by searching for bookmarks to old pages and updating the URLs to the new pages.

The extension focuses on status codes 301 and 308, ignoring all other status codes like 200, 404, 403, and 500. It's important to note that the extension doesn't detect HSTS (HTTP Strict Transport Security) upgrades, as these upgrades occur client-side and don't generate a request to the server.

With Bookmark 301 Updater, only the URL is updated, without any changes made to tags, folders/directories, title, or description. This straightforward approach ensures that your bookmarks remain accurate without any unnecessary modifications.

Overall, Bookmark 301 Updater is a handy tool for keeping your bookmarks up to date, saving you time and effort in manually updating them.