[matchai]

- Multiple Windows

Yes. https://stackoverflow.com/a/29965036

- Telemetry opt-in

Yes. https://code.visualstudio.com/docs/supporting/FAQ#_how-to-di...

[Nullabillity]

> Yes. https://code.visualstudio.com/docs/supporting/FAQ#_how-to-di....

That's opt-out, not opt-in.

[nsriv]

So...opt-out then.