Does anybody understand the copper heatpipes? It mentions virtual vacuum, but my understanding is that heatpipes are typically filled with a liquid that boils

Does anybody understand the copper heatpipes? It mentions virtual vacuum, but my understanding is that heatpipes are typically filled with a liquid that boils and turns to gas as it heats, thus moving up along the pipe and carrying heat further away to allow for a larger contact surface with the heatsink. Are airtop's heatpipes somehow different? What "virtual vacuum" and how does it work?