DFEs: Comma separated list of Data Formats extensions that are to be used before the required search operation is to be performed. Optional.

notFound: The handling option when the search item is not found and an empty string is generated. The search item can be a boundary or an Xpath, depending on the function. Optional.
"Notfound=error", the default value, causes an error to be raised when a search item is not found.
"Notfound=warning" does not issue an error. If the search item is not found, it sets the parameter count to 0, and continues executing the script. The "warning" option is ideal if you want to see if a string was found, but you do not want the script to fail.
Note: If Continue on Error is enabled for the script, then even when notFound is set to "error", the script continues when the search item is not found, but an error message is written to the Extended log file.
Optional.

ordinal: Indicates the ordinal position or instance of the match. In addition to passing a number, you can specify LAST. If you specify All, the parameter values are saved in an array. See Parameter Arrays.
Optional. The default instance is 1.
This attribute does not apply to web.regSaveParamXpath or web.regSaveParamJson.

saveLen: The length of a sub–string of the found value, from the specified offset, to save to the parameter.
Optional. The default is –1, indicating to save to the end of the string.
This attribute does not apply to web.regSaveParamXpath, web.regSaveParamJson,or web.regSaveParamRegexp.

saveOffset: The offset of a sub–string of the found value to save to the parameter. The offset value must be non–negative.
This attribute does not apply to web.regSaveParamXpath, web.regSaveParamJson, or web.regSaveParamRegexp.
Optional. The default is 0.