Messenger & Notifier for Facebook™ is a Chrome add-on developed by Grephy. It provides easy access to messenger.com and notifies users of new posts. With this add-on, users can check messenger.com from their desktop machines by clicking on the toolbar icon, which opens a small UI attached to the toolbar popup. Additionally, users will receive badge notifications for all incoming messages.

It is important to note that Messenger & Notifier for Facebook™ is an unofficial extension and is not affiliated with the official Facebook or Messenger web application or website. It serves as a wrapper to the original messenger.com web-app, making it usable as a browser extension.

Some key features of Messenger & Notifier for Facebook™ include a comprehensive Messenger client in the browser's toolbar, badge notifications for activity on messenger.com, and a customizable UI with all messenger.com functions. The add-on's options page allows users to adjust settings, including the badge-icon text color.