defaultParams property

Optional. Default parameters that will be set for all the execution of this extension. If specified, the parameter values can be overridden by values in [ExecuteExtensionRequest.operation_params] at request time.

The struct should be in a form of map with param name as the key and actual param value as the value. E.g. If this operation requires a param "name" to be set to "abc". you can set this to something like {"name": "abc"}.