The oddly-shaped throat plate insert for Craftsman Miter Saw #137.212290 wasn't too hard to recreate, which is great, since it's been discontinued and no longer available anywhere.
Original part # is 2BK8.
Original part is injection-molded high impact polystyrene, but ABS should work fine. The hot blade may interact poorly with PLA, but I think PLA would also work.
The author hasn't provided the model origin yet.