We KNOW it's not Ilford.
If you wait long enough, one of the Adorama rep, Helen will show up and will tell you, because of confidentiality agreement with the manufacturer, she won't be able to say who made the paper. Simon Galley (of Ilford) has said Ilford does not make any paper for house brand, so we know it's not Ilford.
The box says it's made in EU country.
I tried RC Pearl, FB matte and FB glossy. It's entirely possible FB Matte is made by someone else. It behaves very differently from the rest.