libvirt users - Jan 2014 - Migration: default value for maxdowntime? (QEMU/KVM)

I am wondering what the default value for migrate-setmaxdowntime is when 
using QEMU/KVM.

http://builder.virt-tools.org/artifacts/libvirt-virshcmdref/html/sect-migrate-setmaxdowntime.html

Is the default the same as QEMU's default in this case? I was looking at 
libvirts source and it appears there is no default set within libvirt, 
unless I missed it. I do see qemuDomainMigrateSetMaxDowntime() directly 
enters the monitor to change the value when set with that command.

Any insight/confirmation is appreciated.