When it comes to your Messenger inbox, Facebook thinks that only you and Facebook should have access to the theoretically private conversations contained within.

To that end, reports Engadget, Facebook is testing new ways to secure its app. Specifically, on an unspecified number of iOS devices, the social-media giant has added a second layer of protection to Messenger's inbox. If enabled, users will need to either re-enter their passcode, or engage Touch ID or Face ID before they can read all their juicy messages.

The idea behind the change is simple: If someone gets access to your unlocked device, this security feature provides an additional barrier that will prevent the bad actor from reading your Messenger messages. Which, hey, that's a good thing.

We reached out to Facebook for additional details on the test, like how widespread it is, but received no immediate response.

Engadget was able to get a statement from a Facebook spokesperson — although there's not much there.

"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," noted the spokesperson. “It's an added layer of privacy to prevent someone else from accessing your messages."

It's worth noting, however, that if Facebook truly cared about the privacy of your Messenger messages, then it would enable end-to-end encryption — which it calls "secret conversation" — by default. It does not. That means that Facebook, and by extension law enforcement, is technically able to read your messages unless you dig around in the settings and turn on end-to-end encryption yourself.

For its part, Facebook has claimed that enabling end-to-end encryption by default is "incredibly challenging[.]" Law enforcement, no doubt, is pleased with that view. The Justice Department and the FBI have for years argued that encryption prevents them from investigating crimes that take place on, or are coordinated over, the internet.

SEE ALSO: Why you shouldn't use Facebook's Messenger Rooms: A non-exhaustive list

If none of this concerns you, and for some reason you're still using Messenger over free and privacy-first options like Signal, and you happen to have an iPhone, and by chance you are part of this test group, then by all means drop this new and extra layer of security on your Messenger inbox.

It's not like it will make your inbox any less private than it already is, and it might just keep out some prying eyes.

UPDATE: June 13, 2020, 12:12 p.m. PDT: A Facebook spokesperson responded to our request for comment, and provided the same statement provided to Engadget (included in the original story above). We have updated this story to include a screenshot of the feature, provided by Facebook.