Open the Photos app → Albums → Shared from Cast / WhatsApp.
If you don't want to open the file but need to know what it is: VID-20181029-WA0107.mp4
The filename is a standard system name generated by WhatsApp. It indicates the video was received or saved on October 29, 2018 . Open the Photos app → Albums → Shared
Use VLC Media Player (it plays almost any .mp4). I can help you manage
Because this is a private file from your personal storage or a specific chat, I cannot see the content of the video. However, I can help you manage, identify, or fix it. 📂 How to Find the Video If you are looking for this specific file on your device: