[libvirt-users] Where are libvirt's USB autroredirection settings stored?

[bancfc at openmailbox.org]

For security reasons Debian's libvirt maintainer has opted to disable 
the default behavior of autoredirecting any newly attached USB device to 
a running VM with SPICE USB redirection ports added.

I tried looking for an obvious setting in virt-manager's menus to change 
this but can't see anything. What libvirt/virt-manager configuration 
file is this setting stored so I can change it on demand?