172_720p.mp4 [ 1080p ]

: If you found this in your browser cache or temporary files, it’s a segment of a video you recently watched.

: This is likely a unique ID or index number within a database. In video streaming, it can refer to a specific "profile" or iTag (internal format code) used to identify a stream's settings. 172_720p.mp4

The filename is a generic, machine-generated label typically used by Content Delivery Networks (CDNs) and video hosting platforms to identify a specific version of a video file. : If you found this in your browser