What is the correct Value for JDownloader2's Youtube_SubtitleFilenamePattern?

I am using "jdownloader 2". I've just leaing its "advanced settings"

At the Key "Youtube: Subtitle Filename Patte", I entered the Value as

*VIDEO_NAME*.*EXT*

or as shown in this picture YoutubeSubtitleFilenamePatte.Value

I thought it would produce Subtitle files in format , but the finally resulted files came out as (extra dot).

I don't want that extra dot, but don't know the correct Value.

Please help.

Thanks

charles