This is a housewrap similar to Tyvek, but feels more like fabric than paper.
Another scout leader brought me a small sample to play with. He made a groundcloth for his 2-man tent with it. I was wondering about using it to make a tarp for my son's hammock.
I sewed on it a bit today... sewed a double seam and then attached a piece of nylon to it as I would for a tie-out. I can pull on it without tearing, but there is a bit of stretch (although it bounces back).
This feels heavier than Tyvek, but it's much quieter. It's apparently so new (or rare) that I can't find any smaller pieces to buy on Ebay, or any threads discussing it.