So I buy lots of stuff. I don’t always get to look at it or test it until sometimes years after.

At some point I purchased 168/169 pin PGA sockets to repair 486 motherboards. They came stacked together and wrapped in cellophane. I’ve used a few from time to time.

One bundle was apparently not sockets but interposers. There was a hand written note that said for M6 update only.
Apparently M6 was the code for Cyrix 486dx CPU’s.

They are passive in the sense that there is no voltage regulation circuitry and it appears all pins pass through.

There are however 32 220 ohm resistors in series with an unknown capacitor that connect to each of the D0-D31 pins.

Any idea what these were used for?