Facebook has since confirmed that this is a feature currently in testing and in a statement made to Engadget, a Facebook spokesperson said, “We want to give people more choices and controls to protect their private messages, and recently, we began testing a feature that lets you unlock the Messenger app using your device’s settings.”
If you don’t see the feature available for you yet, don’t panic because like we said, this is a test so probably only a handful of users are seeing them. We’re not sure what you need to do in order to be selected for the test, but if you don’t have it, then you’re not part of it.
This would also not be the first Facebook product/service to offer up such security measures. Last year, Facebook rolled out Face ID and Touch ID support for WhatsApp, offering up a similar way for users to protect themselves and their privacy by making sure that only they get to see the messages they receive on WhatsApp.