*   `Estimator.export_savedmodel()` now includes all valid serving signatures
    that can be constructed from the Serving Input Receiver and all available
    ExportOutputs. For instance, a classifier may provide regression- and
    prediction-flavored outputs, in addition to the classification-flavored one.
    Building signatures from these allows TF Serving to honor requests using the

2A77..2ADB    ; valid                  ;      ; NV8    # 3.2  EQUALS SIGN WITH TWO DOTS ABOVE AND TWO DOTS BELOW..TRANSVERSAL INTERSECTION
2ADC          ; mapped                 ; 2ADD 0338     # 3.2  FORKING
2ADD..2AFF    ; valid                  ;      ; NV8    # 3.2  NONFORKING..N-ARY WHITE VERTICAL BAR
2B00..2B0D    ; valid                  ;      ; NV8    # 4.0  NORTH EAST WHITE ARROW..UP DOWN BLACK ARROW