This filename appears to be a , which is common for files exported from specific surveillance systems, private cloud storage (like Google Drive or Dropbox), or internal enterprise databases.
I was unable to find any specific public information, video summary, or official documentation for a file named . LDNr93lq-21.mp4
If you have viewed the video, what are the key events or subjects shown? The Purpose: This filename appears to be a , which
If this is for a , I recommend checking the manual of the recording device (such as those from Linear ) to see if the filename contains encoded timestamp or camera ID data. This filename appears to be a