Earlier this year, Facebook made a statement saying that they had deleted some old messages sent by CEO Mark Zuckerberg on Facebook's popular messaging app, Messenger. However, regular users can't do this because if you delete a word, it only deletes on your end and not the recipient's end. However, the latest leak of this feature has risen on the internet, as seen in the Tweet below.
Jane Manchun Wong tweeted the unsend feature in action. From the screenshots on her Android device, it seems that if you select a message, you'll see an option that says "Unsend Message" If you click on it, you'll be taken to a screen to confirm you're unsend and you're good to go! Facebook is said to be currently working on releasing the feature to the public, but whether this is true or not is still relatively unknown.