Last modified: 2014-01-17 03:55:32 UTC
I just visited https://www.mediawiki.org/wiki/Special:NewMessages on MediaWiki 1.23wmf7 while not logged in and it was showing messages for me that I have not contributed to. I checked the page source, and wgUser is "null". I think the expected result is that Special:NewMessages never gives results for anonymous users.
It's replicable..