Those are ERA (explosive reactive armor) bricks. Literally armor that provides it's protection by exploding. They are designed to disrupt the copper jet from shaped charges.
They sure fucking did! And it's actually quite common on the heavily armored vehicles. However, it doesn't work on anything thin-skinned as the ERA itself would destroy the vehicle it is supposed to guard.
I recommend watching the whole video as it has lots of good info and great visuals. However, I timestamped the part explaining ERA, here.