Since "Lilu" is a broad term, it could refer to several different things depending on your context: Potential File Origins
: "Lilu" is the name of a popular open-source kernel extension on GitHub used to boot macOS on non-Apple hardware. While the software itself is not a video, you may have downloaded a video guide or tutorial related to its installation.
: It could be a promotional video for a brand or product using that name. Technical Details of MP4 Files
: MP4 (MPEG-4 Part 14) is a digital multimedia container format most commonly used to store video and audio.
A file named is likely a duplicate video file downloaded from the internet or received via a messaging app. The "(1)" in the filename usually indicates that a file with the same name ("Lilu.mp4") already exists in that folder.
: It is universally supported and can be opened on Windows (using Media Player), macOS (QuickTime), and mobile devices.