The "Fsharetv Video Downloader" is not an official product of the Fsharetv team. It is usually a standalone software (often named something generic like Video Proc or Stream Saver ) that uses URL sniffing.
Look for a clean, ad-free downloader with positive user reviews. Avoid sketchy “freeware” that asks for your mother’s maiden name. A few solid options even integrate directly with your browser. Fsharetv Video Downloader