: " mp4 " indicates the MPEG-4 Part 14 container format, which is the most widely supported video file type for mobile and web playback.
While not a standard industry term, it likely refers to one of the following:
: The " 023 " is typically a prefix or index number assigned to a file within a playlist or a batch download process.
Essentially, this instruction tells a program to "download the 23rd item in a list using the smallest possible MP4 file size."
