Because these numeric strings are auto-generated by the platform's servers, the content of the video isn't public unless it's shared in a specific channel or group. However, here is what that file extension tells you and how to handle it: What This File Is

: Files starting with 2_ followed by a long string of digits are almost always internal filenames from Telegram's database.

: The .mp4.7z means it is a video file ( .mp4 ) that has been compressed or "zipped" using the 7-Zip format to reduce its size for easier sharing or storage. How to Open It

: Once extracted, you can use any standard media player like VLC Media Player to watch it.