Remote_control_21.mp4
Filenames like this are frequently used in Alternate Reality Games (ARGs) or "analog horror" series to give the impression of a leaked or "found" government file.
In software development or UI/UX testing, such a file might be used to demonstrate remote execution or media playback controls. How to Investigate the File remote_control_21.mp4
"Proof of concept" videos showing how a hacker can control a target's screen. Filenames like this are frequently used in Alternate
If you have the file and need to identify its purpose, check these metadata points: check these metadata points:

