I am using Rselenium to download file such as (https://www.imf.org/external/np/fin/ert/GUI/Pages/Report.aspx?CU=USD&EX=CSDR&P=DateRange&Fr=628929792000000000&To=637381440000000000&CF=Compressed&CUF=Period&DS=Descending&DT=Blank)
I want firefox to download the file without asking what to do with file, I edited the preferences browser.helperApps.neverAsk.saveToDisk = "application/xml", "text/xml"
but it failed.