I'd say that's almost certainly hosts.cfg. But look for "delayred" in the manual and see where that is supposed to go. Then you'll know.
▸ quoted from Cure4All
From: Cure4All [mailto:user-0ccd3c844281@xymon.invalid]
Sent: Friday, September 27, 2013 08:04 PM
To: xymon at xymon.com <xymon at xymon.com>
Subject: [Xymon] Xymonnet bad tags
Hello, I need help to find which file do I need to edit in order to fix this Warning. Nothing else shows up in the logs. Thank you.
WARNING: The 'bad<TESTNAME>' syntax has been deprecated, please convert to 'delayred' and/or 'delayyellow' tags