MP4 is the most universally supported video format, playable on almost all digital devices, including Windows, iOS, Android, and smart TVs.
If you have access to the file, you can view its specific or creation date by right-clicking the file and selecting "Properties" (Windows) or "Get Info" (Mac). MP4 files explained: How to open and use - Adobe Fu.1.mp4
Some recording devices or screen capture tools use short prefixes like "Fu" (possibly for "Full" or "Future") followed by a sequence number. MP4 is the most universally supported video format,
As an MP4, the file likely follows these industry standards: playable on almost all digital devices
Video editors often use shorthand for draft versions (e.g., "Full 1" shortened to "Fu.1").