Validator revenue takes into account inflation rewards (staking issuance) and transaction fees. Stakers are paid rewards in ETH for validating blocks and processing transactions. On 15 Sept 2022, Ethereum changed their consensus model from Proof-of-Work to Proof-of-Stake — before that date, revenue went to miners (block subsidy + uncle rewards); from that point onwards, all revenue goes to stakers. Chart uses 7-day moving average.