I find it dubious that employees from FAANGs would use a third -party coding environment when most have stringent policies about intellectual property and data

I find it dubious that employees from FAANGs would use a third -party coding environment when most have stringent policies about intellectual property and data sharing. A sandbox app like this would have to go through security review to be approved for corporate use. If available, the company would prefer to just host the app on prems. Therefore I'm really curious how the author can tell it's used by FAANG employees. Corporate emails?