WMV, WMA - Windows Media Formats
WMV (Windows Media Video) and WMA (Windows Media Audio) are Microsoft formats from the late 1990s, largely replaced by MP4 and AAC. Use VLC Media Player to play these files on macOS.
What File Juicer does with WMV and WMA files
File Juicer recognises WMV and WMA files by their file header when the extension is missing. This is useful for files recovered from browser caches or other sources where files are stored without their original extensions.
WMV and WMA files are packaged in the ASF (Advanced Streaming Format) container. See also the AVI and ASF page.