Mongrel - strange start-up message

I am using pretty much the same RoR set up on Ubuntu 7.10, Fedora Core
5, and Windows with Rails 2.0.2, Ruby 1.8.6 and NetBeans 6.1 Beta.
machine is using Mongrel. Both the Linux machines start Mongrel with
this strange message:

It's just saying that a somewhat experimental feature is there.
Signals don't really exist on windows and so I'd guess that is why you
don't get the message. The people on the mongrel mailing list would
probably know for sure.