Fine Uploader get the allowed extensions to use on other parts

I am trying to implement the jquery fine uploader and now i need to get the allowed extension from the uploader and use it in determining if the file is allowed or not to upload on custom function.

There is a method to get the allowed extension but is a private api.

 _getValidationBase: function(buttonId) {
                var extraButtonSpec = this._extraButtonSpecs[buttonId];
                return extraButtonSpec ? extraButtonSpec.validation : this._options.validation;
            },

I cannot find any public api to get the validation/ allowed extensions in fine uploader.

Is there any method to get the allowed extension to use publicly?

Note:

I am using Fine Uploader 5.15.5

If the question is unclear could further add more informations.