*April 1, 2020: The Full Lock feature is now available as a new app for iOS, Focus Lock.
What is the MDM Profile?
Focus Lock requires that you download an "MDM profile" for your phone. MDM stands for Mobile Device Management and it allows a secure third party to prompt an action on your device. In this case, the third party is Focus Lock and it is remotely hiding your apps for you and then pushing them back onto your phone based on a schedule. Only you decide when this feature is activated and Focus Lock will only hide your apps if you have explicitly enabled Focus Lock.
Why is this necessary?
Apple doesn't allow a third party app to hide or restrict access to your phone without certain verified permissions. Using the MDM is just the way we have to engineer the feature, and work with Apple's iOS software the way it is.
You're safe with Focus Lock