They are these. They've held up pretty well. I have noticed esdf (instead of wasd) are smoothing out a bit, but not bad overall. Really happy with how they look in person!
Black 108 Key Cherry Profile PBT Double Shot Side-lit Shine Through Translucent Backlit keycaps for MX Mechanical Keyboard Filco (Only Keycap) https://a.co/d/6Cy6JHQ