Files with no public trace may be:
Because this appears to be private or age-restricted content, you would typically find it on the official site of the studio that produced the "WMBCV" series or through specialized video archives. Files with no public trace may be: Because
Obsolete formats and personal videos often survive on: Files with no public trace may be: Because
This is likely a user-named file from an older personal collection—not a published commercial or indie release. Files with no public trace may be: Because