FB Unseen is a Firefox add-on designed to enhance user privacy by blocking read receipts on Facebook. With this extension, users can read messages without notifying senders, providing a seamless chatting experience. Installation is straightforward, requiring no additional configuration, making it accessible for all users. The add-on is lightweight, as it only needs to disable a single line of code to function effectively.

A notable feature of FB Unseen is the option to manually mark messages as read. This allows users to maintain discretion when replying to messages, as it prevents the sender from seeing whether the message has been read or not. Overall, FB Unseen is an efficient tool for those who wish to manage their online interactions on Facebook without unwanted notifications.