[libvirt] DUID-LLT (DHCPv6 with time-based UUID generation) - how does it work in libvirt?

Reading the examples, I'm not sure how to get DUID-LLT working (which is unfortunate, as it seems to be the default of dhclient). I got DUID-LL working, but DUID-LLT has a timestamp - which is generated, AFAIK, by the client - how can the XML contain the correct DUID-LLT entry? The examples in the docs: <host id="0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66" ip="2001:db8:ca2:2:3::2" /> Somehow assumes the time is 18:aa - no idea how it 'guessed' this is what the client would use. DUID-LL was easy and worked, as it just a prefix + the MAC address. TIA, Y.