DateStamp formatting string to be used altogether with the file downloaded or uploaded.
Its template is equal as for the FormatDate AmigaOS function,
common codes (a few ones) are the following:
%c - same as "%a %b %d %H:%M:%S %Y"
%d - day number with leading 0s
%m - month number with leading 0s
%Y - year using four digits with leading 0s
%H - hour using 24-hour style with leading 0s
%M - the number of minutes with leading 0s
%S - number of seconds with leadings 0s
For full details check the Amiga's AutoDocs