Used by Variable/Connection.

https://github.com/apache/airflow/blob/894741e311ffd642e036b80d3b1b5d53c3747cad/airflow/secrets/metastore.py#L32

"""A JSON serializable representation of operator.
    All operators are casted to SerializedBaseOperator after deserialization.
    Class specific attributes used by UI are move to object attributes.
    Creating a SerializedBaseOperator is a three-step process:
    1. Instantiate a :class:`SerializedBaseOperator` object.
    2. Populate attributes with :func:`SerializedBaseOperator.populated_operator`.
    3. When the task's containing DAG is available, fix references to the DAG
       with :func:`SerializedBaseOperator.set_task_dag_references`.
    """
    _decorated_fields = {"executor_config"}
    _CONSTRUCTOR_PARAMS = {
        k: v.default
        for k, v in signature(BaseOperator.__init__).parameters.items()
        if v.default is not v.empty
    }
    def __init__(self, *args, **kwargs):