We know free apps make money by selling your info, how about one (Adware Doctor) that is paid to protect you actually, pilfers data secretly to a server in China (bypassing App store sandbox restrictions).

Adware Doctor
The app sidesteps Apple's sandbox and covertly collects users' browser histories and then transfers it to a server in China—which is blatant violations of Apple's developer guidelines.

Adware Doctor collects sensitive users' data—primarily any website you've visited or searched for—from all the popular web browsers including Chrome, Firefox, and Safari, and then sends that data to Chinese server at hxxp://yelabapp.com/ run by the app's makers

What's more? Adware Doctor originally was named "Adware Medic," which was clearly designed to mimic a different AdwareMedic app acquired and rebranded by MalwareBytes in 2015

Wardle contacted Apple weeks ago about the issue, but the company did nothing about it

https://thehackernews.com/2018/09/mac-adware-removal-tool.html