This could be a "slug" or a placeholder name used in software development or automated uploading. If you found this in a specific context—such as a URL, a specific website's directory, or a diagnostic log—that information would be key to identifying its exact meaning.
: Which often name clips based on timestamps or camera ID sequences. 21800mp4
Knowing if it was in a URL , a file directory , or a specific piece of software would help in providing a more detailed write-up. This could be a "slug" or a placeholder