https://www.vice.com/en_us/article/pke9k9/facebook-wanted-ns...
"The Facebook representatives stated that Facebook was concerned that its method for gathering user data through Onavo Protect was less effective on Apple devices than on Android devices," the court filing reads. "The Facebook representatives also stated that Facebook wanted to use purported capabilities of Pegasus to monitor users on Apple devices and were willing to pay for the ability to monitor Onavo Protect users."