The essentials
Layer-2 systems process activity outside a base chain and settle commitments back to it. Rollups publish data and use validity proofs or dispute systems to support the state transition.
What to consider
Bridge contracts, sequencers and upgrade keys introduce additional assumptions. Optimistic withdrawals may involve a challenge delay; fast exits can rely on third-party liquidity.
Put it into practice
Compare data availability, withdrawal procedures and governance controls. A familiar token ticker on a new network does not imply identical security or liquidity.