A few questions questions related to Instance refresh prep:

1. Email Logs (if you want old records of these, download them before the maintenance) - what email logs, and how do I download them
2. Manually-Generated Email-to-Case ThreadIDs (don't manually generate your own!) - What counts as manually generating thread IDs?  Email to Case adds them in our org, as well as our auto-response email templates.  
3. How do I know if we use locally cached certificates?