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

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?