I'm guessing you mean Trp LoE Film (66) Bronze 6mm-13mm Air
As you can see from the Description:
Window construction from EnergyPlus 8.0 WindowConstructs.idf
dataset.
If you open the DataSet folder from E+, three files are of interest, and they all have informative stuff located at the top of the file.
From WindowConstructs.idf#L1593:
Construction,
Trp LoE Film (66) Bronze 6mm/13mm Air, !- Name
BRONZE 6MM, !- Outside Layer
AIR 13MM, !- Layer 2
COATED POLY-66, !- Layer 3
AIR 13MM, !- Layer 4
CLEAR 6MM; !- Layer 5
! U=1.703 SHGC=0.306 TSOL=0.21 TVIS=0.455
If you look at WindowGlassMaterials.idf#L12:
! COATED POLY-xx Coated polyester film with nominal visible transmittance of xx percent
So this is a Coated polyester film with nominal visible transmittance of 66%.