The Call Volume All Strikes is the sum of all call options' that was traded across all available strikes and expiration dates. Volume is the number of contracts for a specific strike and expiration that traded hands. The sum of volume across all available options is an important indicator of the underlying stock or ETF's options liquidity on the day and also in general.
If the Setup you defined in your Brutus Options Ranker Strategy uses call contracts, then the Call Volume All Strikes criterion may be added to your strategy tree as a measure of overall liquidity in the underlying stock or ETF's options at the time of rank.
You will always want to maximize this criterion. Considering the volume of all call contracts for the day gives an excellent measure of how liquid the options were throughout the previous trading day.