I'm still not sure what it is but I used a bit of it as the backing for a fidget quilt. That was quite an experience! I machine sew my bindings on the back first then turn them to the front and machine stitch there. Usually I don't pin, I simply sew 6" or so at a time, line up the next bit and keep going. It usually works fine. Usually....
The binding fabric kept sliding around on the pile of the fabric. Sometimes it moved in too far, sometimes it went off the edge. Yikes!! I managed but it's not my best work.
Next time I use this for a backing, I'll plan to simply fold the backing to the front. It does not appear to fray but with the fidget quilts I always straight stitch the binding to the front then go around again with a zig zag. I think that should keep the raw edge from fraying. It's too thick to fold twice as I usually do when I pull binding from the back.
It made a cozy fidget quilt though.