If you are looking for a specific or trying to identify which app generated this filename, it is common for brands like Vantrue, Viofo, or 70mai to use randomized alphanumeric strings for cloud-synced or protected clips.
The camera automatically saves and locks a video clip when it detects an impact or motion while the car is parked. C21VKWvLFvVAm2r5.mp4
Real-time logging of speed and coordinates directly onto the video file. If you are looking for a specific or
Capturing synchronized footage from both the front and rear of the vehicle simultaneously. C21VKWvLFvVAm2r5.mp4
The ability to overwrite the oldest unprotected footage to ensure the camera never stops recording.
The "useful feature" likely refers to one of the following common dashcam functionalities: