Review for Provider for Google Calendar by per4mance
Rated 1 out of 5 stars
After installing add-on my thunderbird didn't start again and I had to cancel the process.
Second try worked but couldn't find any button or hint how the add-on works. Did a test with new calendar entry but couldn't find the entry in Google Calendar.
For now the add-on doesn't do what it promises.
To create your own collections, you must have a Mozilla Add-ons account.