On-chain staking
An overview of eligibility criteria (including geographic restrictions) for On-chain staking can be found here.
Asset Code Migration
This will be a gradual change applied to accounts over time in batches. The transition will be represented in your Kraken Pro Ledger as "Migration".
Any asset code ending with a ".S" represents an On-chain staked balance. For example, XTZ.S represents On-chain staked Tezos while XTZ are non-staked Tezos.
Any asset code ending with a ".M" represents an Opt-In Rewards balance. For example, BTC.M represents Opt-In Rewards Bitcoin while BTC are Bitcoin are not Opted-In.
Any asset code ending with a ".P" represents a Parachain balance. For example, DOT.P represents assets bonded to parachains.
You may notice staked balances when looking over your Ledger History.