.err file extension

[qwerty04]

I have a folder "tube downloader" and inside the folder I have a file "youtube." It won't open. I looked @ the details and it says it is a ".err" file extension. Does anyone know anything about why the file is a .err file extension name youtube?

 

[Droids]

There was an error in downloading the file, or the download was blocked. Just delete it. It might be a plain text log file too with some error details in it.