Thanks for mentioning Super User's BSD Cross Reference (bxr.su)! Apparently there are many more OpenGrok installations nowadays than it used to be 5 years ago.
Never heard of that website, seems useful. Unless I am missing something, however, it seems that while the OpenBSD, NetBSD and DragonFlyBSD sources are up to date, the FreeBSD sources are out of date from 09-Dec-2013.