FlowAlgo - Algo Score is an experimental feature that is currently in beta so please don't put much weight on it for any trading decisions.
In simplest terms, the Algo Score is the measure of aggressiveness behind an order.
Here's what makes up the Algo Score.
The total order premium vs the days to expiration.
The contracts current day volume vs the open interest of a contract.
The order's contract quantity vs the current day's volume.
The total order premium.
The order type (Multi-exchange sweep, single exchange sweep, option block trade)
As well as a few other data points we can't publicly mention at the moment.