Every options trade prints with a size, a strike, an expiry and whether it hit the bid or lifted the offer. Aggregating that stream shows where capital is being committed and with what urgency, which is information the share price alone does not carry.
The signal people look for is a large block, far out of the money, lifted at the offer in a short-dated expiry. That combination is expensive, decays fast and only makes sense to someone expecting a move soon.
It is easy to over-read. A large print may be one leg of a spread, a hedge against an existing share position, or a market maker laying off risk. Treat the flow as evidence of where attention is concentrated, not as a copyable trade.