This is a market on if The Merge will occur on the Ethereum mainnet as described in EIP-3675 (or any successor to EIP-3675) by the resolution time, September 1 2022, 11:59:59 PM ET, transitioning the Ethereum blockchain to proof-of-stake.

If the first proof-of-stake block (defined in EIP-3675 as TRANSITION_BLOCK) is produced before the resolution time, this market will resolve to "Yes".
Otherwise, the market will resolve "No".

Note, that forks to the execution layer and the consensus layer implementing EIP-3675 will not have any impact on the market resolution. Only the actual occurrence of The Merge will be considered.