Here is some music -- or is it an image ? or some text ? or some video ?
Only Matrix surfers are able to recognise it, or the computer
A format and a header for each file
The suffix or the type mime express the type of content, the format, then
the file starts with a header that gives more information on the way to read the
If a file was a map, the format would be the legend and the header the scale
and the direction of North
HTML, Gif, JPEG, MOV etc are file formats (for data, encapsulation of data)