Since the filename is randomized, you can find out what the video is by:
: When Google Photos generates a name like this, the original filename (e.g., "Birthday_Party.mp4") is often replaced. However, the original metadata—such as the date taken, GPS location, and camera settings—is usually still embedded inside the file's EXIF data. Why does this happen? If you see this filename, it is likely because: B63kXx7MNixC1CPxJ4SeIsvkruFHZrRU.MP4
: You saved a video from a shared link or album where the original filename wasn't preserved. Since the filename is randomized, you can find