Well, they say they won't use customer data for model training.
https://www.dropbox.com/ai-principles
But, it isn't clear whether or not they'd get that consent passively, like "by continuing to use our services" after sending a little email "hey we updated our privacy policy, thought you should know, k thx bye"
How do you unblock? I don't see any settings in Sync for unblocking a community you block in this way. Is it only accessible through the account settings by logging into your home instance with browser?
Also, is there an easier way to add to the community filter list in Sync?