[criddell]

I don't think it's something special that Google is doing. I suspect they are just using the built-in App Groups functionality.

Basically, it's a way for different apps from the same developer to share information via a data container.

[sneak]

Correct. Apple is leaking the data between apps for them.

[criddell]

I wouldn’t call it leaking when it’s done by design and is something any developer of multiple apps can do.

For example I wouldn’t say Linux is leaking data every time an application uses fopen.