Okay I found that now. I actually found that earlier but I thought it was not right because I get this:
This is not right since the container in the front is supposed to be solid metal.
I then tried inverting the opacity map with a OneMinus node but and this happened:
This looks like the map works correct, only inverted. For example, the label on the bottles are fully invisible.
If I remove the node again, it’s just as bad as before.