Do you remember or what the conversation was about around that date?
Because this name is unique to the device it was saved on, only the sender or the person who has it in their WhatsApp "Sent" or "Media" folder knows what is inside. VID-20200619-WA0339mp4
Go to the chat from June 19, 2020 , and look through the shared media. Do you remember or what the conversation was
Open your gallery or file manager and search for "WA0339." VID-20200619-WA0339mp4
It is impossible to provide the content of that specific file because is a generic filename generated by WhatsApp. The filename follows a standard naming convention: VID : Video file.
If you use Google Photos or iCloud, search for that filename in your backup.