Permatex makes a 'high temp' Anti-seize paste with copper in it. Perhaps that is what you are looking at.
-30°F to 1800°F
Spark plug threads installed in aluminum, exhaust manifold bolts, engine bolts, oxygen sensors, knock sensors, thermostat housing bolts, fuel filter fittings, and battery cable connections.
The 'regular' anti-seize contains a lot of aluminum.
-60°F to 1600°F
For easy removal of spark plugs, cylinder head and exhaust head bolts.
Then there is the 'super high temp' Nickel Anti-Seize:
Protects metal parts from seizing and galling at temperatures up to 2400°F.
Note, however, that brake use is NOT a suggested application for any of these. Link to Permatex products
They do make Ultra Disc Brake Caliper Lube
for this purpose, which has a full synthetic base.
I use this stuff from CRC/Sta-Lube