To me it looks like some kind of coating to get the painting to stick. I believe fiber glass or similar would crack rather than bend.
Living room: Kii Three/BXT with Control.
Den: Tannoy Precision 8 iDP with TS112 iDP subwoofer.
In the cupboard, waiting for a sibling: 1st gen. Phantom Silver running DOS1
My Phantom Voyage
Den: Tannoy Precision 8 iDP with TS112 iDP subwoofer.
In the cupboard, waiting for a sibling: 1st gen. Phantom Silver running DOS1
My Phantom Voyage