Because this name is specific to the person who originally saved or shared the file, there is no public "guide" or information available for it online. : Short for "Video."
The filename is a generic name automatically generated by WhatsApp . VID-20210822-WA0189mp4
: If you have the file on a computer, right-click it and select Properties (Windows) or Get Info (Mac). Sometimes the "Origin" or "Description" fields contain hints, though WhatsApp usually strips this data for privacy. Because this name is specific to the person
: The date the video was saved or sent (August 22, 2021). WA : Stands for "WhatsApp." or famous event
: If the video is a clip from a movie, tutorial, or famous event, you can take a screenshot of a clear frame and use Google Lens to search for the original source.