**Screenshots**
If applicable, add screenshots to help explain your problem.

**Environment (please complete the following information):**
 - OS: [e.g. Windows 10]
 - Browser [e.g. chrome, safari]
 - Version [e.g. 13.5.0]

**Additional context**

Fess also contains a Crawler, which can crawl documents on a [web server](https://fess.codelibs.org/14.12/admin/webconfig-guide.html), [file system](https://fess.codelibs.org/14.12/admin/fileconfig-guide.html), or [Data Store](https://fess.c...

,a.each(l,function(a,b){if(i=k.indexOf(b)>-1)return!1}),i}),i||(a.formUtils.warn("Trying to upload a file with mime type "+k+" which is not allowed"),e(this,"wrongFileType",l.join(", "),h))),i}return a.formUtils.warn("FileReader not supported by browser, will check file extension"),a.formUtils.validators.validate_extension.validatorFunction(b,f,g,h)},errorMessage:"",errorMessageKey:"wrongFileType"}),a.formUtils.addValidator({name:"extension",validatorFunction:function(b,c,f,g){var h=!0,i=this,j=d(c);return...

        }
        return OptionalObject.empty();
    }

    @Override
    public OptionalThing<Locale> getRequestedLocale(final RequestManager requestManager) {
        return OptionalObject.empty(); // means browser default
    }

    // ===================================================================================
    //                                                                      Basic Override