What iz it? I haven't a clue!

Several years ago I aquired a complete darkroom from an estate sale, the familiy had no idea about the equipment, but backed up and took it all as per their request. there was a chest freezer full of film and paper but also the source of my question. In the bottom was a box materal about the thickness of linolium kind of grey and rolled up. I know the ol feller was into alternative processes, so I have assumed that was part of it but have no clue. I will try and find it and shot a pix of it, but it has me curious?

it could be for printmaking...relief carved
As in ink and brayerina press.

Without seeing it, I'd guess it's linoleum for printmaking. I took a class in printmaking many years ago and we worked with linoleum. Other than that, I haven't a clue.