Earlier quoted context omitted.
Your employer, of course, is Google; I know this from my own tussles with Google's OSPO, which exists primarily to ensure that engineers don't have lives outside of Google.
[Disclaimer: I work at Google.] I see no conclusive evidence in the parent comment that proves it's Google. I would've actually guessed Apple. My understanding is that Google actually has a reasonable process for this, and that people have taken advantage of it to start or contribute to projects in a personal capacity.
They do approve side projects in rarer cases where it has nothing to do with Google's business - for example, my friend recently wrote an app for sex positions. But most things that I want to work on have a messaging / ML / AR component to them somewhere so I haven't felt comfortable building anything while I've been employed there. Hence the main reason I'm leaving Google at the end of the month, to build those things :)