Compared with StaFiHub, we call other projects as the target chain, such as Cosmos, IRISnet, etc.
A pool is an interchain account or a multisig account of target chain to gather origin token(such as ATOM/IRIS) and invoke staking related calls such as Delegate, Undelegate and Withdraw reward on the target chain to earn more tokens.
As a multisig account, it has no private key but an address and several sub-accounts and a threshold.
As an Interchain Account, it is a module account which has no private key too and can only be created and controlled by the controller chain(such as StaFiHub).
There might be several pools for a rToken.
The rToken relay service plays a role as cross chain bridge to connect StaFiHub and target chains.
A relayer is a member to run a rToken relay service. Each relay service requires a relayer to send proposals to StaFiHub. And if we use a multisig account as a pool, the relayer should be a sub-account of the multisig account.
Era was introduced as a concept of period to solve problems like when the pool should invoke delegate and undelegate call. Pools invoke all the necessary calls on the target chain once and only once for each Era. The epoch of era on the mainnet will be one day.
The exchange rate of rToken is used to calculate how many rToken to mint or burn.