PoS and Burn and Mint are considered the same model, and the current bridging transactions largely use these methods instead of Plasma.

The plasma bridge was an earlier bridging process when Polygon was known as the MATIC network. It's mainly phased out now because Plasma is costly and not commonly used anymore.

Currently, Polygon uses a Burn and Mint bridging model, where tokens are burned on the origination chain and re-minted on the destination chain, maintaining a constant cross-chain supply.

The Ethereum contract 0x401F6c983eA34274ec46f84D70b31C151321188b, labeled as 'plasma bridge,' is still used in some cases, but generally, it's not associated with the contemporary Plasma model due to the evolution of sidechains and L2 solutions.