The number of 'yes' votes cast by the committee of validators which are attesting to the validity of the produced block in each slot.

Each Epoch, up to 64 committees of at least 128 validators are algorithmically selected per slot for block production and attestation. For each slot, one validator out of the committee is selected to propose a block, whilst the remaining validators are responsible for casting attestation votes.

This is the Point-in-Time (PiT) variant of Attestation Count. PiT metrics are strictly append-only and their history is immutable. The historic data does not necessarily reflect the best current knowledge, but the information at the time when a data point was first computed. PiT metrics are ideal candidates for applications in model backtesting and related quantitative purposes. Read our article on PiT metrics for more information.