The extension indicates a 7-Zip ( .7z ) compressed file containing a MP4 video file ( 335.mp4 ).
Always ensure the source of compressed files is trusted, as archives can be used to hide malicious software.
You will need archive software such as 7-Zip (Windows), The Unarchiver (macOS), or similar apps on mobile to "extract" or "unzip" the .mp4 file before it can be played in a media player.
