Single-fact: what did the proposer of the latest block ACTUALLY get paid (priority fees + direct coinbase transfers — the value that reaches the validator, not the noisy block-value proxy)? Returns {block, proposer_payment_eth, builder, tx_count} plus a 1h aggregate {samples, mean_eth, median_eth, p90_eth, max_eth}. Per-block history export: /v1/premium/builder-bids.csv ($0.05, CSV or JSONL).