A Forest River rep replied to my email question. The answer is Alpha Ply. She directed me to the manufacturer for how to care for it. Product Care & Warranty - Alpha Systems, LLC
A word of caution because, the final sentence on the care document says "Alpha's membrane is quite inert and will resist weathering well. It does not require the periodic application of products to protect it from ultra-violet light or ozone. In fact, these products can often cause damage to the roof membrane. "
I hope this helps someone else in the future.