- Generic ephemeral volumes, a new alpha feature under the `GenericEphemeralVolume` feature gate, provide a more flexible alternative to `EmptyDir` volumes: as with `EmptyDir`, volumes are created and deleted for each pod automatically by Kubernetes. But because the normal provisioning process is used (`PersistentVolumeClaim`), storage can be provided by third-party storage vendors and all of the usual volume features work. Volumes don't need to be empt; for example, restoring...

    *   `CategoryCrossing`: create new categorical features representing
        co-occurrences of previous categorical feature values
    *   `Hashing`: the hashing trick, for large-vocabulary categorical features
    *   `Discretization`: turn continuous numerical features into categorical
        features by binning their values
*   Improved **image preprocessing** layers: `CenterCrop`, `Rescaling`