“Malo periculosam, libertatem quam quietam servitutem.”
I think gold.
A metallic coating of indium-tin-oxide is added to the canopy to reflect the radar waves, giving it a golden tint.
I think it absorbs radar. Reflecting it back is bad for stealth.
The Navy EA-6B had something similar. I was told it was gold, to protect the crew from the radiation from the jamming pods. But I was a mech, not avionics, so it could have been BS. I do know they were very pricey.
Gold film is used for window heat, the coating is something other; indium according to the comments.
Reflects radar not back to the source. Absorption of any rf is not good to the body or any material.
Back in the 80's, IIRC, it was discovered that you could use the gold coater system, employed to coat items for electron microscope viewing, to coat the lenses of sunglasses to get better performance. Couple atoms thick? Still required a clear coating for scratch resistance, I think.
The original windshields and hatch screens on the F-111 were two layers of tempered glass with an atomized layer of gold sandwiched between them. Was to protect crew members from nuclear blast radiation and flash. Were changed out in mid 70's for birdproof polycarbonate screens. The windshields were lab tested by firing 4 lb. chickens out of a cannon into the screens. We had two F-111As return to Mtn. Home AFB, Idaho in the spring of 1980 with windshield damages from flying through the ash plume. The pilots dang near lost both aircraft in their "Quest for Scientific Knowledge" as all 4 engines flamed out. The windshields were scratched to hell and back and absolutely opaque. Every leading edge on the wings, vertical stabilizers and the radome were extremely pitted. Close call for both aircraft, and a ton of work for maintenance...