This is just a copy of the last version of The Cavern Links Checker as it existed at Userscripts.org. This was copied from:

http://userscripts-mirror.org/scripts/review/29222.

It is highly unlikely that this script will be updated. A newer re-write of this script is here:

https://openuserjs.org/scripts/yahavatar/Yahs_GM_Linkchecker

Unbelievably, this script was installed 2,498,618+ times. That's the last count that Userscripts tracked...

Thanks,
yah.