The localized date string on Windows reveals local time
https://blog.torproject.org/blog/tor-browser-602-released#comment-191587 mentioned it first and https://blog.torproject.org/blog/tor-browser-65a6-released#comment-225152 pointed it out again:
On Windows the localized Date string reveals the local timezone (again). I reproduced that with an en-US 6.5a6 bundle on a Windows 7 machine. On my Linux box it is not an issue.