@DoomsdaysCW that's perfect; it confirms it's half inch hardware cloth:
The cleared-out section is then covered with a wire fence mesh with ½ inch x ½ inch openings.
And the previous / original Maine release indicates galvanized:
galvanized steel hardware fencing over the cut stems.
That should account for the "coated" look. It's possible they also had some other coating on there, but the wording in the different write-ups never seem to talk about a chemical component to the mesh solution, and at least seem to focus on the mechanical aspects of it.
The spots where we have knotweed infestations are more often on riparian type banks, which could make this technique tough to apply, but honestly I'm willing to give it a shot to see if I can apply it. Half inch galvanized steel hardware cloth is readily and fairly cheaply available. It definitely seems worth a shot, especially if the writeups are accurate about still allowing native flora to push through and help reestablish alternative cover and try to crowd out the knotweed.