What Is the Role of a “Supermajority” in PoS Finality?

In PoS systems like Ethereum, a supermajority (typically two-thirds of the total staked ETH) of validators must sign and attest to a block for it to be considered "finalized." This consensus threshold ensures that the block is accepted as irreversible. If a supermajority were to attempt to reverse the block, they would face massive economic penalties (slashing).