: The string could potentially be a product key or a serial number for a software or hardware product. If it's related to a Fortinet product (as hinted by "fortinet" within the string), it might be used for licensing or identification purposes.
: The file only takes up as much physical space on the host as is actually stored within the virtual disk, rather than its full defined capacity.
sudo cp fgtvm64kvmv747mbuild2731fortinetoutkvmqcow2 /var/lib/libvirt/images/fortigate.qcow2