Can Google see any events in my other local Thunderbird calendars?

[John Kanu]

This is a security question. I don't know where else to ask this question, but I'm wondering what data Google can see if any from my computer. Let's say I have a local calendar in Thunderbird called Local, and I've subscribed through Provider to a Google calendar called Google-calendar. When Thunderbird synchronizes Google-calendar through Provider, is any data from Local sent to Google?

My thinking: from the description of GDATA at https://github.com/kewisch/gdata-provider/wiki/FAQ I gather that Provider can read from and write to Google Calendar, while Google calendar passively receives and processes read and write requests. However, when calendar data is sent to Google to be written into the subscribed calendar, is any calendar data outside of the local instance of the subscribed calendar sent to Google?

Thanks