Can you link me what you’re talking about? I’m searching for it and having trouble finding the thing you’re describing. The only info I find is about their spam detection (which I already knew about but doesn’t sound like it’s the thing you’re talking about.)

I’m not aware of any code from Google it requires. What history of stealing data does signal have?

Can you explain a little more what you mean?

The only part that isn’t open source is their spam filter.