This page lists where most of the stuff related to virtualization is located on a Linux operating system. This is based on Fedora. But it should be similar for other distributions.
libvirt configuration file/etc/libvirt/libvirtd.conf
/usr/share/edk2/ovmf/OVMF_CODE.fd
/usr/share/edk2/ovmf/OVMF_CODE.secboot.fd
/var/lib/libvirt/qemu/nvram
The Nvram contains the saved state of the UEFI configuration.
/var/lib/libvirt/images