On page 98 of Jet Substructure at the Large Hadron Collider: A Review of Recent Advances in Theory and Machine Learning the author writes;
Redacted phase space: Studying the distribution of inputs and the network performance after conditioning on standard physically-inspired features can help to visualize what new information the network is using from the jet. Training the network on inputs that have been conditioned on specific values of known features can also be useful for this purpose.
I cannot find other references to conditioning features. What does that mean?