The photo looks like R.Tape Conform series paper masking tape, which would be fine for lasering, and could very well be what is used on proofgrade. It is not a poly product, however, and as far as I know R.Tape does not make a product called Glassmask…
The listing shows paper, says poly, and doesn’t mention the name brand shown in the photo. Will you get a roll of clear polyester film? A roll of paper R.Tape Conform? Even if the “poly” film is polyester (and so laser-safe) it doesn’t mean it will be cleaner burning, and will certainly not be cleaner engraving (than paper masking).
That said, I don’t know if I trust this particular listing.
While I personally prefer their competitor TransferRite, R.Tape makes fine product as well, and is normally available through the same suppliers, like uscutter.com and signwarehouse.com (who sell to the public), and industry-direct suppliers like Grimco and Fellars