The fee recipient is an Ethereum address that receives transaction fees from block production, separately from the proposer reward that accrues on the beacon chain.
The execution client is not required to follow the fee recipient suggestion and may instead send the fees to a different address — only use execution clients you trust!
Any validator without a per-validator recipient set will fall back to the `--suggested-fee-recipient` option if configured or the withdrawal address of the validator.
For example, `nimbus_beacon_node --suggested-fee-recipient=0x70E47C843E0F6ab0991A3189c28F2957eb6d3842` suggests to the execution client that `0x70E47C843E0F6ab0991A3189c28F2957eb6d3842` might be the coinbase.
If this Nimbus node has two validators, one of which has its own suggested fee recipient via the keymanager API and the other does not, the former would use its own per-validator suggested fee recipient, while the latter would fall back to `0x70E47C843E0F6ab0991A3189c28F2957eb6d3842`.