Once you've downloaded the "Facebook Research" VPN (sometimes called the "Project Atlas"), the app prompts you to "install our root certificate". In this way, you give Facebook almost unlimited access to your mobile device. In return, Facebook only pays you $ 20 (in the form of gift cards) per month.  A well-known fact that VPN is designed to protect your privacy and allow you to stay online anonymously. The great example of such apps is   https://www.vpnunlimitedapp.com/en, but isn't the Facebook Research app. Facebook app does the exact opposite. The Facebook Research VPN reportedly collects data about:

Banned from the App Store

An investigation by TechCrunch revealed everything that Project Atlas had to hide. It seems that Facebook has tried to circumvent the test system of Apple-targeted. The app violates Apple's policies, so Facebook misused Apple's pure app distribution system to bypass the App Store. A few hours after the story was published, Apple banned the app - before Facebook could voluntarily remove it. However, the app is still available on Android devices and will continue to collect the personal information of thousands of people for as long as they can.

Trusted VPNs

A VPN should protect your privacy and ensure your online anonymity. The Facebook Research VPN could do exactly the opposite, but there are many honest VPN providers out there.