keyplyr - 3:14 am on Jul 31, 2012 (gmt 0)
Actually, it can be from any person on any range that is using the safety settings that check for virus/malware/etc in Chrome browser, and possibly other browsers.
/undefined means the web page hasn't been classified as safe or otherwise yet. There's a couple more prepended tags that mean other things but I can't remember right now.
I forward them:
RedirectMatch 301 ^/undefined$ http://www.mysite.com/$1