They’re called cutters. They take perfectly good prints and cut them up to sell for profit.

Please do not buy.

That link you shared is printed from digital anyway. But it’s from a print. So it was printed to a negative, a theatrical print was struck from the digitally printed negative, and then that seller has cut up the print to make those strips.

Or are they doing something to put maybe a Blu-Ray or dare I say DVD rip onto film stock?

There are services that allow you to do this, but I can tell this is cut up of a real print just from looking at it. There’s printed-through damage from the negative easy to spot if you know what to look for.