If you meant something else—like a technical topic, a video editing workflow, a file-naming convention, or an update process for media servers—please clarify the context, and I’d be happy to help with a legitimate, informative article.
fc2ppv3966770mp4, which suggests it is an MP4 file. MP4 files can contain H.264 or H.265 video streams and AAC-LC or AC-3 audio streams, among others.